̽��ֱ�� of Cambridge - sperm

Opinion: ̽��ֱ��biggest sperm come in the smallest packages – and other odd facts about male sex cells

Anonymous — Thu, 19 Nov 2015 14:32:59 +0000

Most people probably think of sperm as the microscopic tadpole-like things wriggling around in human semen. But there is an astonishing amount of diversity in the size, shape and number of sperm produced by male animals. In fact, despite performing the very same function in all animal species (fertilising eggs), sperm are the most diverse cells found among animals.

This diversity is a product of evolution. Every animal’s sperm has evolved to meet the needs of the individual animal that produces it. For example, new research published in Proceedings of the Royal Society B shows that the number and size of sperm produced by a mammal depends on the size of the female reproductive tract. Studying these kinds of adaptations helps us to better understand the incredible diversity we see in sperm across animal species.

Tiny animals can have massive sperm

Sperm length varies by several orders of magnitude across species, from the tiny sperm of the porcupine (0.0003 cm) to the gigantic sperm of the fruit fly (6 cm), which is more than 20 times the length of the fly. ̽��ֱ��fruit fly’s sperm looks like a wound-up ball of string that unravels once inside the female’s even longer reproductive tract.

̽��ֱ��number of sperm produced by different animals also varies enormously. Humans produce approximately 100 million sperm per ejaculate, while rams can produce 100 billion. Groups of sperm can even work together. Sperm in some species are known to team up and form a “train” that swims faster than individual sperm.

Promiscuous females mean more sperm

Much of the variation we see in the size, shape and number of sperm produced by different species is thought to be the product of competition for fertilisation among the sperm of different males. This is a type of sexual selection, only relatively recently described, known as “sperm competition”. In species whose females mate most promiscuously, there is strong pressure on males to invest more heavily in sperm, to ensure that one of their own little soldiers is the one that wins the battle for fertilisation.

This has led to an extraordinary array of different warfare tactics. These species, in general, produce more sperm, as more soldiers on the ground gives you a numerical advantage. It may also be advantageous to produce bigger sperm, which are faster and able to outcompete the sperm of other males in the race to the eggs.

Bigger females mean smaller sperm

Sperm can also vary depending on the size and shape of the female body. To accommodate this, sperm have to be able to swim far and fast enough, to successfully reach the eggs. In general, bigger sperm swim faster, so males should produce numerous, large sperm. But males only have finite resources to allocate to sperm production and may face trade-offs.

This means that evolutionary pressure to increase sperm size will inevitably lead to a reduction in number, and vice versa. As mentioned, recent research found that among mammals, males of smaller bodied species tend to invest in fewer, larger sperm, while males of larger species tend to invest in more, smaller sperm. This is because the females of larger species have bigger reproductive tracts and so more (but smaller) sperm can spread across the greater space and have more chance of encountering an egg.

Manlier males have lower quality sperm

As sperm can be costly for the body to produce and resources are limited, males can also face trade-offs between producing sperm and other characteristics useful for reproduction. For example, species in which males invest more in big bodies and horns, or deep voices have been shown to produce less sperm.

In humans, men with more attractive voices have been shown to have worse quality sperm. It seems that males are faced with a trade-off between investing in traits that are useful for competing with rivals, or those that increase the chance of fertilising an egg. They can’t have everything.

Males can control sperm quantities

Amazingly, males seem to be able to control the amount of sperm they produce. There is evidence that males vary the amount of sperm in ejaculates, depending on the quality of the female, or the risk of sperm competition. In humans, men looking at explicit images of two males and one female (“sperm competition images”) have been shown to produce more mobile sperm than those looking at explicit images of three females.

Female animals who mate with more than one partner are also thought to have some control over the sperm that fertilises their eggs. So-called, “cryptic female choice” occurs when females use physical or chemical mechanisms to control each male’s chances of fertilisation. This is well described in a number of animal species, providing a mechanism by which females can bias the outcome of reproduction. For example, in some species, females will mate with several males and then selectively fertilise eggs with only the largest sperm or sperm from males with more compatible immune system genes.

Jacob C Dunn, Lecturer in Human Biology, ̽��ֱ�� of Cambridge

This article was originally published on ̽��ֱ��Conversation. Read the original article.

̽��ֱ��opinions expressed in this article are those of the individual author(s) and do not represent the views of the ̽��ֱ�� of Cambridge.

Jacob Dunn (Division of Biological Anthropology) discusses why sperm are the most diverse cells found among animals.

Joyce Harper, UCL, Wellcome Images

Sperm cells

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

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Attribution-Noncommerical

Study finds increased DNA mutations in children of teenage fathers

fpjl2 — Wed, 18 Feb 2015 09:49:59 +0000

A genetic study of over 24,000 parents and their children has shown that the children of teenage fathers have unexpectedly high levels of DNA mutations.

Mutations, the result of DNA copying errors during cell division, can occur in different cells of the body and at different times during life. Some, such as those that occur in 'germ cells' – which create sperm or eggs – cause changes affecting the individual's offspring.

Previously, it was thought that germ cells in both boys and girls go through a similar number of cell divisions, and should have roughly the same rates of DNA mutation by the time an individual reaches puberty.

Now, a new study shows that the number of cell divisions – and consequently DNA mutation rates – experienced by the germ cells of teenage boys is six times higher than for those of girls, and that DNA mutations passed down to the children of teenage fathers are higher as a result.

Researchers say the increased DNA mutations in the reproductive cells of adolescent boys could explain why the children of teenage fathers have a higher risk for disorders such as autism, schizophrenia and spina bifida.

Men produce germ cells throughout their lives, and it was previously assumed that DNA mutation in germ cells increased as men get older – more cell division and greater DNA mutation has occurred as men age.

However, the latest results show that the germ cells of adolescent boys are an exception to this aging rule.

Researchers have shown that male germ cells go through around 150 cell divisions by puberty, compared to the 22 cell divisions experienced by female oocytes (immature egg cells). This raises in tandem the rates of DNA mutation incurred by cell division in the germ cells of teenage boys – creating higher chances of hereditary disease in children conceived by adolescent fathers.

̽��ֱ��researchers say that this could be the result of unknown cell divisions during male childhood or a spike in DNA error during puberty – although the reasons are currently unclear.

Prior to the new findings, male germ cells were thought to undergo 30 divisions by puberty. ̽��ֱ��results overturn previous notions that the younger the man, the less cell division and the less risk of DNA mutations in germ – and later sperm – cells.

In fact, researchers say that – while more work needs to be done – these initial findings furthermore indicate that sperm cells in teenagers have approximately 30% higher rates of DNA mutation than those of young men in their twenties, and that teenage boys have similar levels of DNA mutation in their sperm cells to men aged in their late thirties and forties.

“It appears that the male germ cells accumulate DNA errors unnoticed during childhood, or commit DNA errors at an especially high level at the onset of puberty. However, the reason for this is not yet clear,” said geneticist Dr Peter Forster, a Fellow of Murray Edwards College and the McDonald Institute at the ̽��ֱ�� of Cambridge, who conducted the study with colleagues from the Institute of Forensic Genetics in Münster, Germany.

“Possibly the DNA copying mechanism is particularly error-prone at the beginning of male puberty. Or, sperm production in boys may undergo dozens more cell cycles – and therefore DNA copying errors – than has previously been suspected,” he said.

Either way, the textbooks may well need to be rewritten as a result of the new findings, says Forster, which are published today in the journal Proceedings of the Royal Society B.

̽��ֱ��research team used DNA from blood and saliva samples taken from 24,097 normal parents and their validated biological children from areas of Germany, Austria, the Middle East and West Africa.

̽��ֱ��researchers analysed a type of DNA known as ‘microsatellites’ – simple, repetitive sequences of DNA that only mutate as a result of cell replication, providing the team with a natural ‘cell-cycle counter’ which they used to track the number of times a cell divides, and consequently the rate of mutations through DNA copying error.

Through comparative analysis, the research team discovered the increased DNA mutations in children of teenage fathers, and that mutations are six times higher in male sperm cells during onset of puberty than in female oocytes.

While this means that the children of teenage fathers have increased chance of abnormality, Forster points out that the risk is still very small: perhaps around 2% as opposed to a general average abnormality risk of 1.5%.

̽��ֱ��team hope to develop the cell-cycle counter technique used in the study and apply it to cancers, in order to better estimate the age of such conditions in individuals, and the number of cell divisions between the initial cellular malfunction and tumour growth.

New research reveals that the sperm cells of adolescent boys have more than six times the rate of DNA mutations as the equivalent egg cells in adolescent girls, resulting in higher rates of DNA mutation being passed down to children of teenage fathers. ̽��ֱ��findings suggest that the risk of birth defects is higher in the children of teenage fathers as a consequence.

Sperm production in boys may undergo dozens more cell cycles – and therefore DNA copying errors – than has previously been suspected

Peter Forster

Professor Stefan Schlatt, ̽��ֱ�� of Muenster

Section of normal testes of a young man

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Females protect offspring from infanticide by forcing males to compete through sperm instead of violence

fpjl2 — Thu, 13 Nov 2014 19:08:52 +0000

Previous research has shown that infanticide by males is widespread in many mammal species, but most commonly occurs in those species where females live in social groups dominated by one or a few males.

Outsiders will fight dominant males for access to females. When a rival male takes over a group, they will kill the infants of previously dominant males to render the females ‘sexually receptive’ again, so that they can sire their own offspring. This may be the main cause of infant mortality in some species, such as Chacma baboons.

Now, a new study published today in the journal Science shows that these brutal acts are strategic; males may only have a short time in charge before they themselves are deposed, and want to ensure the maternal investment of females is directed towards their own future offspring for the longest time possible.

However, the females of some species - such as the mouse lemur - have evolved a highly-effective counter-strategy to stop males from killing their offspring: by having as many mates as possible in a short amount of time. By confusing the paternity of the infants, known as ‘paternity dilution’, any male act of infanticide risks the possibility of killing his own offspring.

In such species, reproductive competition shifts to after copulation, not before - so that the most successful male is the one whose sperm outcompetes those of the others. This leads to males producing ever larger quantities of sperm, leading in turn to increases in testis size. ̽��ֱ��testes of male mouse lemurs swell 5-10 times larger during the breeding season.

“In species in which infanticide occurs, testis size increases over generations, suggesting that females are more and more promiscuous to confuse paternity,” said lead author Dr Dieter Lukas, from ̽��ֱ�� of Cambridge’s Department of Zoology.

“Once sperm competition has become so intense that no male can be certain of his own paternity, infanticide disappears - since males face the risk of killing their own offspring, and might not get the benefit of siring the next offspring.”

Closely related species that differ in infanticide and testes size include chimpanzees (males commit infanticide) versus bonobos (males have not been observed to kill offspring). Bonobos have testes that are roughly 15% larger than those of chimpanzees.

Male Canadian Townsend voles don’t commit infanticide, and have 50% larger testes compared to infanticidal males of close relatives the North American meadow voles, says Lukas.

He conducted the research with colleague Dr Elise Huchard, who is now based at the CNRS Centre d’Ecologie Fonctionnelle et Evolutive in Montpellier.

Fifty years ago, observations of wild Hanuman langurs shattered previous depictions of monkey groups as peaceful, supportive societies, says Lukas, as new males that had just taken control of a group of females frequently killed all juveniles.

Subsequent observations have accumulated over the years on various mammals to show that infanticide by males is a widespread phenomenon, occurring in species from house mice to lions and gorillas. In some species, he says, the biggest risk faced by infants might not actually be predators or diseases, but the adult males of their own species.

In the latest study, Lukas and Huchard compiled and compared detailed field observations for 260 mammalian species to show that male infanticide occurs in species where sexual conflict is most intense, and reproduction is monopolised by a minority of males. ̽��ֱ��researchers’ findings indicate that infanticide is a manifestation of sexual conflict in mammalian social systems.

“While it had previously been suggested that infanticide might be an evolutionary driver in mammalian societies - leading to females allying themselves with other females or forming bonds with a specific male in order to defend their offspring - we’ve now shown that this isn’t the case: male infanticide is a consequence of variation in sociality, most commonly occurring in species where both sexes live together in stable groups,” said Lukas.

̽��ֱ��researchers say the new study supports the idea that infanticide isn’t a general trait present in all species, but is strategic and occurs only when it is advantageous to males. ̽��ֱ��study reveals the reversible nature of male infanticide, and that it is successfully prevented by the ‘paternity dilution’ strategy of female sexual promiscuity.

Added Huchard: “Male infanticide appears and disappears over evolutionary times according to the state of the evolutionary arms race between the sexes. Although infanticide may not have contributed to shape the diversity of mammalian social systems, it has deeply influenced the evolution of sexual behaviour and sex roles.

“This study also highlights that some of the greatest challenges faced by mammals during their lifetime come from others of their own species.”

Inset images: A male mouse lemur with large testes (credit: Cornelia Kraus). A Chacma baboon with dead infant (credit: Alice Baniel)

Latest research shows the females of some mammal species will have many mates to ensure unclear paternity, so that males can’t resort to killing their rival’s offspring for fear of killing their own. This forces males to evolve to compete through sperm quantity, leading to ever-larger testicles. Scientists find that as testis size increases, infanticide disappears.

Once sperm competition has become so intense that no male can be certain of his own paternity, infanticide disappears

Dieter Lukas

Elise Huchard

Baboon fight

Yes

Tiny sperm, big stories

amb206 — Wed, 10 Sep 2014 08:00:00 +0000

In 1881 a German couple – Herr and Frau B - were trying to get pregnant with no success. They consulted Dr Levy, a gynaecologist based in Munich, for help. Levy was determined to approach the problem in a scientific manner and make a thorough investigation into the man’s fertility. Over a period of several months, Levy made 12 pre-arranged home visits to the couple to conduct a study that he knew to be fraught with “obnoxiousness”.

To determine whether the ejaculate contained living spermatozoa, Levy took mucus from the woman’s vagina and cervix shortly after the couple had had sex and while the woman was still resting in the marital bed. ̽��ֱ��microscope Levy brought with him revealed that Herr B was sterile, a condition that a tough regime of physical exercise and the faradisation (treatment with electrical currents) of his testicles would prove unable to change. After trying for years to conceive a child, Herr and Frau B were reported to be content to have done their duty by exploiting every possibility that modern medicine had to offer.

̽��ֱ��case of Herr and Frau B, and the ordeal they underwent 130 years ago, is taken from the medical literature that forms the primary source of research by historian Dr Christina Benninghaus, who has worked at Cambridge for the past two years. At a conference later this week she will give a snapshot of her research into the history of human reproduction in the decades around 1900 and, in particular, the emergence of medical studies of male infertility.

“Knowledge about some vital aspects of human reproduction was hazy. ̽��ֱ��concept of hormones had not been developed and the connection between menstruation and ovulation had yet to be fully understood. However, infertility was already an important sphere of medical intervention. Inflammation of male and female reproductive organs was treated with ointments, douches and massages. Women, and sometimes men, were sent to watering places to improve their health, couples were offered sexual advice, and attempts at artificial insemination were not unheard of,” said Benninghaus.

Surgery was also undertaken to increase the chances of conception. And it was often, though not exclusively, directed at the female body. Attempts at widening the cervix and at repositioning the uterus were not only painful, but also dangerous, and from the 1870s their effectiveness was very much doubted. To spare women from unnecessary surgery, gynaecologists increasingly considered the possibility of male sterility and advocated sperm testing.”

̽��ֱ��late 19th century witnessed a quest for rational forms of diagnosis and a fascination with microscopy. "However, sperm testing was by no means easy to introduce," said Benninghaus. "Medical and religious objections against masturbation severely hampered the collection of semen. Men found it hard to accept a diagnosis that both destroyed their hopes of fathering children and appeared to threaten their bodily experience of potency."

Experts debated how best to engage with male patients unwilling to agree to testing. Benninghaus explained: “Physicians were eager to spread knowledge about male sterility through talks and publications. And they warned the public that men often infected their wives with gonorrhea, a major cause of both male and female infertility. ̽��ֱ��association of male sterility with lazy or dead spermatozoa – an image that would not have made sense to earlier generations – now entered the public imagination.”

Benninghaus is one of a dozen speakers who will, during the course of the two-day conference, consider the narratives that surround sperm: our historically changing understanding of its biological make-up and its contribution to the process of generation, its materiality as a marker of collective health, its identity as a scientific object and a commodity, and its symbolic value within shifting perceptions and negotiations of masculinity.

As an experience central to life itself, and with technologies offering new possibilities, human reproduction recognises no neat disciplinary boundaries. When Benninghaus sat down with Cambridge ̽��ֱ�� sociologist Dr Liberty Barnes to plan a meeting that would encourage wide-reaching conversations, they opted to bring together historians, sociologists and anthropologists to look at the topic of sperm, and male infertility, from a broad range of perspectives.

Barnes said: “What’s cool about the conference is that we contacted a bunch of male infertility scholars and invited them to submit paper abstracts -- and nearly all of the submissions were about sperm. Tiny sperm tell big stories. Sperm serve as something akin to cultural artefacts for telling all kinds of stories about human history and social problems.”

Since the 1960s a revolution has taken place in reproductive technologies – such as IVF, sperm and egg donation, and surrogacy – and has been accompanied by shifts in social attitudes. Increasingly available across the globe, these developments have challenged the meanings of family and kin, reproduction, and opened up new routes for mothering or fathering a child. Most recently, the use of mitochondrial transplantation (resulting in an embryo with genes from three biological parents) has led to intense ethical debate.

Advances in reproductive sciences have inspired new strands of academic research. ̽��ֱ��ethical debates surrounding the new technologies, and their very real consequences for the lives of people worldwide, have encouraged historians to look more closely at the history of reproduction and how past narratives continue to inform the way we navigate these matters today.

Recent studies have re-examined common assumptions like the belief that infertility was routinely ‘blamed’ on women primarily to save men from the social stigma of impotency. Benninghaus’s research reveals that this was far from the case. Her study of the medical literature from the second half of the 19th and the early 20th century reveals that medical experts took a great interest in male sterility in order to help families have children.

“Increased efforts to identify the causes of male infertility were prompted by a deadlock in the diagnosis and treatment of female sterility, paired with a continuous demand for treatment, growing interest in microscopy and the possibilities it offered, and a new understanding of the dangers of venereal disease,” she said.

“ ̽��ֱ��impulses for greater research into the morphology and the physiological functions of sperm came not just from within science and medicine but also from patients who expected medicine to provide an answer to their quest for a child. Already a century ago, couples experiencing infertility, had to make choices regarding the kind of treatment they wanted to pursue and they had to come to terms with diagnoses that could be devastating.”

̽��ֱ��proliferation of assisted reproductive technologies (ART) around the globe in recent decades has inspired the work of many sociologists and anthropologists. While most ART research has focused on women’s experiences, this week’s conference considers the role of men (and sperm) in new reproductive science. For example, Barnes’s research shows that infertile men are willing to undergo rigorous and painful procedures to increase their sperm production and restore sperm to their ejaculate to make “natural” conception possible.

Sperm stories are about more than making babies. Robert Pralat, a PhD candidate in sociology at Cambridge, will draw attention to the fact that semen, the fluid containing sperm, can be both reproductive and destructive. Pralat will talk about the different roles semen plays in donor insemination and in HIV infection. He said: “It’s interesting how little dialogue there has been between scientists working on assisted reproduction and those that work on sexually transmitted diseases. After all, they are interested in the same substance! An interdisciplinary conference is a great opportunity to make those kinds of connections.”

Pralat’s research explores two challenges that face British healthcare: the shortage of ‘high-quality’ sperm, with many donation programmes relying on supplies from overseas, and the ‘surplus’ of infected semen, with new HIV infections among gay men at an all-time high. He said: “It’s ironic that while fertility clinics struggle to provide their services because of the lack of sperm, the uncontrollable spread of semen poses the main challenge for HIV prevention.” Pralat will ask whether the two areas of scientific study and clinical practice can learn anything from each other in addressing these challenges.

Because sperm can be easily assessed and analysed, they now serve as indicators of national health, enabling researchers to track changes in count, size, shape, and make-up across time and space. Dr Janelle Lamoreaux, a medical anthropologist at Cambridge, will look at the work of scientific laboratories in China that study environmental degradation by observing changes in sperm cells across the Chinese population. Her paper explores the ways both scientists and social scientists envision and establish the relationship between exterior environmental problems and interior reproductive health concerns through sperm.

"Sperm has become an important object in analyses of intertwining human and environmental health in China. ̽��ֱ��anxiety around declining national sperm counts is certainly about the threat to male reproductive capacity that reduced sperm quality and quantity might bring. But this anxiety is also about China’s potentially infertile future as it relates to environmental destruction amid rapid industrialisation, development and social change. Anxieties about the nation, masculinity, and environmental destruction are produced and reproduced through sperm," she said.

While much social scientific research on male infertility concentrates on clinical settings, Lamoreaux's research among toxicologists, who study sperm as a means of understanding toxic exposures, offers a perspective that stresses the connections between male reproductive health and environment, economy, and industry.

Con/Tested: Sperm Science, Sterility and Masculinity takes place at the Department of Sociology in Cambridge on 11 and 12 September, 2014.

̽��ֱ��conference is sponsored by: the Wellcome Trust; the Sociology of Health and Illness Foundation; ReproSoc, the reproductive sociology research group led by Dr Sarah Franklin; and Generation to Reproduction, a research programme led by Dr Nick Hopwood in the Department of History and Philosophy of Science.

Christina Benninghaus has recently taken up a position at the ̽��ֱ�� of Gießen. Her two-year stay at the Department of History and Philosophy of Science at the ̽��ֱ�� of Cambridge was made possible by a senior “Mobility for the Humanities” Fellowship provided by the Gerda-Henkel Foundation.

Inset images:In 1909, Magnus Gustaf Retzius (1842-1919) published these detailed images of morphological variations in human sperm.
(reprinted by Weisman, Abner I., Spermatozoa and Sterility. A Clinical Manual, New York: Paul B. Hoeber, 1941); a sperm race, 1888 (Gerard, J, Nouvelles causes de stérilité dans les deux sexes); syringe for artificial insemination (Giles, Arthur E, Sterility in Women, London: Frowde and Hodder & Stoughton); a modern sperm bank in China (Ayo Wahlberg).

Sperm will take centre stage at a conference in Cambridge later this week as researchers from a wide range of disciplines gather to consider the narratives that surround the male gametes necessary for human reproduction.

Sperm testing was by no means easy to introduce. Medical and religious objections against masturbation hampered the collection of semen. Men found it hard to accept a diagnosis that destroyed their hopes of fathering children and appeared to threaten their bodily experience of potency.

Christina Benninghaus

Gerard, J., Nouvelles causes de stérilité dans les deux sexes

Image from a popular French guidebook for infertile couples, published in 1888

Yes

Male infertility is ‘culturally invisible’, finds research

fpjl2 — Thu, 01 May 2014 09:13:38 +0000

Even though male infertility is responsible for half of all cases of infertile couples, decades of misogynistic limelight on infertile women has left a ‘categorical hole’ in medical systems, with very few male fertility specialists and no official board certification for practitioners in the US, says a medical sociologist.

Some men seeking treatment end up further damaged by malpractice – prescribed testosterone, for example, which arrests sperm production – resulting from treatment by specialists in the wrong areas, such as a general urologist or their wife’s doctor.

And those that do manage to engage with male infertility specialists are often fed information about their disorder through metaphors that mask infertility – frequently involving traditional male activities such as plumbing, sport or car mechanics – to the point where two thirds of infertile men interviewed for the study simply didn’t consider themselves infertile.

“This is not some kind of deep-seated denial on the part of these men. There is an entire culture and medical system that makes it possible for men to be infertile and not even realise it,” said Dr Liberty Barnes from the ReproSoc group in the Department of Sociology, who has authored the book Conceiving Masculinity based on the research.

“Male infertility is as prevalent as female infertility, but it’s invisible in our society. While female infertility support groups, blogs, news and literature abound, male infertility is hidden from public view.

“In fact, most cases of male infertility are referred to IVF clinics – a process in which women bear the brunt. For many, male infertility is repaired in female bodies.”

Barnes spent over 100 hours shadowing doctors in five clinics in different states right across the US, as well as interviewing many of the couples involved (men and women separately).

Most infertile men, even those who do self-identify as infertile, are able to ‘intellectually reframe’ their infertility issues as a medical condition somehow separate from their self, explains Barnes.

“This separation of body and self, while rare in female infertility, is the standard coping mechanism in men – that their ‘messed-up plumbing’ is not their fault and in most cases repairable.

“Many men cling to the notion that if you have a problem that can be fixed, you don’t have a problem. Instead of telling these men they’re infertile, you hear doctors saying ‘oh, it’s just an issue with your blocked exhaust’.

“ ̽��ֱ��doctors actually provide men with the linguistic strategies to separate body from self.”

Culturally, male fertility is intrinsically bound up with ideas of virility, machismo and sexual potency because it hinges on that very essence of manliness – semen. As William, a businessman in his late thirties interviewed for the research, puts it: “Men should be able to gush sperm all over the place”.

For Barnes, the prevarication around male infertility is symptomatic of widespread cultural nervousness to expose masculinity as in any way fragile. Masculinity is equated with power; protecting and expressing power is a key function of societies and states. In the book, she cites the global media panic around a 1992 study showing sperm counts were dropping.

Male infertility hits masculine identities – from the personal to the national – right where it counts, says Barnes. One interviewee described his desire for fatherhood as “kind of the only purpose of life”. Another said his infertility led him to “doubt the toughness” of his penis.

Consequently, once a man is diagnosed, almost as much effort is taken to socially alleviate this perceived trauma to masculinity as to treat it medically. When interviewed, doctors reeled out a progressive rhetoric. But in the infertility clinics Barnes found a culture designed to enforce gender stereotypes and bolster masculinity.

“Every doctor I spoke to and medical seminar I went to, I heard time and again: we’ve got to help society move past archaic ideas that reproduction is women’s work. Then when I was in the clinics, it was complete immersion in traditional gender ideology: penis jokes, talk of balls – everything was power and virility,” said Barnes.

Diagnoses were shrouded in metaphors invoking factories/bridges/engines – technological achievement hiding biological failure. One doctor that Barnes shadowed, when prescribing hormone treatment to boost testosterone, would tell patients that side effects include “the urge to hit a ball really hard or drive really fast”. Barnes describes this claim as scientifically debatable.

̽��ֱ��assumed functionality of male sexual biology also translated to the first experience of the clinic – the collection cup. Men describe being pushed into a room or even just behind a curtain with no instruction beyond “fasten the lid tightly”.

Medical institutions assume men can masturbate under any conditions, will enjoy it, and be able to shoot semen straight into a cup, says Barnes. Some interviewees told her the semen they provided was both of particularly poor quality and limited due to stress and the amount they were able to catch. In fact, most men found this confusing and uncomfortable – especially when bluntly confronted with the choice of ‘performing’ or extraction by needle from the testicle.

Barnes found the extraordinary lack of medical professionals specialising in male infertility as opposed to those in female infertility – as well as absence of official board certification for treating male infertility – to be part of a damaging cycle:

“When I spoke to organisations about this hole in the system, they would tell me it’s because it’s not needed. Men aren’t coming forward for treatment, so there appears to be little demand. But then those that do struggle to find help, which – combined with the social stigma – means that many give up.”

There is a medical and social price to pay, she says. Research into male infertility is nowhere near as advanced as that for female infertility. And societal silence on the subject means men who want and may well be able to have children if treated are not – or being treated by the wrong people.

Among what medical specialists there are, the cultural invisibility of infertile men is inherently conflicting, says Barnes. On the one hand, male infertility doctors complain about the lack of attention the topic receives. But on the other, they realise this invisibility protects men and masculinity by suppressing the issue.

“If you promote male infertility as a label to encourage more men to come forward for treatment, you will have a harder time helping them pretend they’re not actually infertile,” she said.

Research for a new book reveals a culturally sanctioned suppression of dialogue around male infertility – despite it being equally as common as female infertility – to the extent that many infertile men receiving treatment still don’t actually consider themselves infertile.

If you promote male infertility as a label to encourage more men to come forward for treatment, you will have a harder time helping them pretend they’re not actually infertile

Liberty Barnes

Stefanie Reichelt

Illustration of sperm

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New conceptions: single mothers by sperm donation

amb206 — Thu, 25 Apr 2013 11:45:00 +0000

Earlier this month, we were given the sad news that Professor Sir Robert Edwards had passed away. A Nobel Prize winner, scientist, and fellow of Churchill College, Professor Edwards has received much international acclaim for his significant contribution to the field of reproductive medicine. Here in Cambridge, with colleague Patrick Steptoe, he pioneered in vitro fertilisation, a method to facilitate family-building in the face of infertility. Yet, although the scientific implications of IVF were well thought-through by the duo, the extensive social, ethical and philosophical debates which ensued as a result of their work could not have been anticipated.

Twenty five years on, it is clear that assisted reproductive techniques have raised fundamental questions about the relationship between technology and society, and the role of science in human experience. And while IVF at the outset was explicitly used to assist traditional family-building, today technology has enabled lesbian and gay couples and single men and women worldwide to become parents, causing much deliberation, discussion and debate among professionals, politicians, and the wider public.

At the Centre for Family Research, our team, headed by Professor Susan Golombok, is committed to obtaining empirical evidence on the psychological, social and emotional well-being of parents and children in families formed through assisted reproduction. Having conducted research on hundreds of families of different shapes and sizes, we have learnt that what seems to be most important is not how families are formed or structured, but the quality of family relationships and experiences. One of our most recent research projects focuses on single women who have used a sperm donor to have a child.

In 1990, when the UK government first legislated about the use of assisted reproduction, it was stated that clinicians needed to consider a ‘child’s need for a father’ in deciding whom to offer treatment. In practice, we know that some fertility clinics were already offering, and continued to offer, treatment to lesbian couples and single women, but the ‘need for a father’ was only recently replaced by the ‘need for supportive parenting’ when the legislation was last amended – in 2008.

Many of the arguments against single women using sperm donation assume that these families are likely to face similar issues to those that might affect single-parent families by divorce, such as financial or emotional difficulties. It is often assumed that women who want to use fertility treatment on their own will fit a middle-class, career-focused, 40-something stereotype, suddenly struck by the sound of their ticking biological clock.

This group of women has been widely criticised for the pursuit of a non-traditional path to parenthood which ultimately, it is argued, deprives children of the right to know, and have a relationship with, their biological father. In fact, concerns are raised not only by politicians and the wider public, but by professionals working in fertility treatment services. Clinic staff have questioned whether single women have the adequate material and social resources, and psychological and emotional skills, required to parent effectively. It is often assumed that these women’s single status is indicative of their inability to maintain a successful romantic relationship. This being the case, it is supposed that single mothers by sperm donation will lack the qualities necessary for good parenthood.

Our latest findings at the Centre for Family Research indicate not only that the cohort of single women accessing sperm donation may be more diverse than often assumed, but that concerns about the functioning of their families may be based more upon misinformation than anything else. In our work, we have so far been welcomed into the homes of over 40 single mothers by sperm donation. We have met their children, their families, their friends and, sometimes, their pets, and have been entrusted with significant and often deeply personal information about their experiences. So who are these women, why have they chosen this path to parenthood, and what are their families like?

̽��ֱ��women we have seen come from a variety of socioeconomic backgrounds, and they differ vastly in their experiences of education and employment. They have ranged in age from their early 30s to their early 50s, with some women initially accessing fertility services as 20-somethings. Only one woman we visited described her decision to use fertility treatment as a result of her career choices earlier in life. In fact, the majority of mothers discuss their decision as resulting from not having a suitable partner at the time they decided to have a child. Contrary to clinical opinion, most of the women in our study have previously been in long-term relationships, and several have cohabited with a partner. Some have had children in these relationships, and others have previously been married.

But why do these women want to become single mothers? ̽��ֱ��answer is that in many ways, they don’t. ̽��ֱ��majority of women we have visited have described how they had always assumed they would have children within a traditional two-parent family, and would have preferred this to be the case. However, they – like the majority of people in the UK today – want to have children, and they want to do so in a way they see as safe and honest, and supported by the services available to them.

When talking about having chosen their specific sperm donor, mothers have described different approaches, including choosing from a sperm donation website in the company of friends, to asking very little information of clinic staff about the donor they have been matched with on the basis of shared physical characteristics. Some mothers tell their family, friends, and their children about their use of a donor, while others do not share this information so readily, and others have opted to refrain from disclosing the information, until their children – who, in our study, are currently aged four to eight – are older.

At odds with the assumption that single women using a sperm donor intentionally deprive their children of a father, most of the mothers we have seen explicitly acknowledge the possibility that their use of a donor may have consequences for how their children feel about their families. Many reflect upon the significance of male role models for their child’s development, and several highlight how they have fostered relationships between their male family members and friends and their children for this reason.

In fact, it seems fair to say that none of the mothers parent single-handedly: they all receive practical and emotional support from family, friends, and others, in raising their children. And although they do see clear differences between their experiences of parenthood and the experiences of their married friends, these differences are not always seen in a negative light. Mothers mostly distinguish between the good and bad families they are familiar with. Their judgments are based upon whether the people in these families are happy and healthy, rather than how many people are in them.

Having now spent over a year listening to their stories, and sharing in mothers’ experiences, it seems reasonable to suggest that politicians, professionals, and the public might do well to take the lead from these mothers in assessing their families in a similar way: irrespective of family structure. Instead of relying on a single stereotype of single mothers by sperm donation, our focus should remain on research which continues to look closely at the well-being of the mothers and children within these families.

Most fundamentally, the debate ignited by Edwards and Steptoe back in 1978 must now move beyond arguments in favour of the traditional family, comprised of two married, heterosexual parents and their 2.4 children. In other words, the need for new conceptions – of family life in general, and of single motherhood specifically – is now clear.

Sophie Zadeh is an ESRC-funded PhD student at the Centre for Family Research, ̽��ֱ�� of Cambridge. Her research with Dr Tabitha Freeman and Professor Susan Golombok focuses on the experiences of single women who have used a sperm donor to have a child, and explores the psychological, social and emotional well-being of mothers and children in these families.

Sophie Zadeh, a PhD candidate in the Centre for Family Research, is contributing to a new study of the well-being of single mothers by sperm donation and their children. Her initial findings confound many of the assumptions about this group of women.

Why do these women want to become single mothers? ̽��ֱ��answer is that in many ways, they don’t.

Sophie Zadeh

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