Every few years, a new study appears sounding an alarm about dropping sperm counts, cuing sensational headlines about the end of men and scholarly concerns about the robustness of the data. Yet amid all the debate about the number of sperm, there has been much less attention on the emerging science of what’s happening inside these little cells, and how a man’s age and health can damage the genetic material in sperm.
My question is: What took so long? After more than a century of studying every possible way that women’s age and women’s behaviors and women’s exposures to toxins can affect reproduction, why are we only now learning basic information about how men’s health affects reproductive outcomes?
This gap — and in particular, our dearth of knowledge about sperm — isn’t natural or inevitable. It can be traced back to the earliest days of medical specialization, when doctors positioned the male body as a neutral medical “standard” and the female body as “reproductive” — leaving us with a “missing science” of men’s reproductive health.
During the latter part of the 19th century, when the medical profession began carving up the body into distinct specialties, reproduction could have become the basis of a unified specialty that incorporated both women’s and men’s bodies. Instead, gynecology and obstetrics, two of the earliest specialties, focused solely on women’s reproductive organs (and merged into OB-GYN in the 1920s and ‘30s). In effect, women’s reproductive parts and processes were hived off from general medicine and designated a distinct realm of knowledge and treatment.
To this day, women are encouraged to schedule regular medical visits to have their reproductive organs examined. Public health campaigns offer all kinds of advice about women’s pre-conception health and age-related fertility. And government labels warn women about toxic chemicals in beverages, medicines and buildings.
In contrast, even as the male body was positioned as the “standard body” for biomedical research throughout the 20th century — the template for further investigation into the cardiovascular system, the brain, and so on — there was scant research on its reproductive aspects. In part, this is the result of a cultural belief that sex is binary: Traditional views of male and female as distinct and even “opposite” categories meant that since women were defined as reproductive, men were defined as not reproductive.
A clear indication of how difficult it’s been to link men’s bodies to reproductive health is the futile attempt to launch a medical specialty called “andrology” — an effort that failed outright in the 1890s and gained only a bit of traction starting in the 1970s.
The topic of men’s reproductive health continues to hover around the edges of multiple specialties — urology, sexual health, infertility — without serving as the focus of any one in particular. Though men are advised to get regular cancer screenings starting in middle age, there are no recommendations that men have their reproductive organs examined regularly, and almost no public health campaigns mention the significance of men’s health for reproductive outcomes.
To be sure, it is women who get pregnant and bear children, so it makes sense that there would be more medical and public health attention to women’s reproductive health. It does not follow, however, that men’s reproductive health should receive almost no attention.
These dynamics repeat again and again: There is still no contraceptive pill for men, for example, and their birth control options remain limited to condoms and vasectomy — the same options they had a hundred years ago. Women can hardly pick up a magazine without being reminded about their biological clocks, while most men have no idea that paternal age can affect reproductive outcomes.
Researchers are just now filling in crucial details about how men’s health can pose risks for their children. Using the label “paternal effects,” scientists and clinicians have concentrated on three factors: a father’s age at the time of conception, what he consumes (alcohol, drugs, smoking, diet), and his exposures to toxic substances at home, work and in the environment.
Some of these factors appear to influence not only pregnancy outcomes, such as miscarriage and birth weight, but also birth defects, childhood illnesses and even adult-onset conditions. For example, with every passing year, older men are more likely to develop new mutations in their sperm, which have been linked to an increased risk of autism and schizophrenia in their offspring.
Yet in my research interviewing men about reproduction, I learned that many remain unaware that a man’s health can have implications for his children. They might have heard the news that men’s behaviors or exposures can affect fertility, by reducing sperm count or causing these cells to be misshapen or sluggish. But the emerging science of paternal effects goes further, suggesting that men’s health can affect not only the number or shape of sperm but also its genetics.
Take, for example, cigarette smoking: Men who smoke before conception can reduce their sperm count and spur genetic changes inside these cells, especially during the two to three months it takes sperm to grow in the body. If the sperm is then able to fertilize an egg, the resulting child faces a higher risk of cancer.
Writing in the American Journal of Epidemiology a decade ago, scientists said that men who are planning to have children should be “strongly encouraged to cease smoking.” Yet warnings like these are not reaching the general public, in no small part because of the lack of medical infrastructure focused on men’s reproductive health.
Figuring men into the reproductive equation could happen in a variety of ways. Health-care providers can disrupt the implicit association of reproductive health with women’s health by explicitly offering patients of all gender identities information about the importance of paternal effects.
Biomedical researchers can work to identify the precise levels of risk posed by men’s age, behaviors and exposures, alone and in combination.
Federal health agencies and professional medical associations can develop materials to educate the public about how men’s health can affect children’s health.
Engineers of fertility apps could add notices about the significance of sperm health.
And high school teachers responsible for health classes or sex education can incorporate this information into the curriculum. (Indeed, in interviewing 40 men about reproduction, I learned that high school is often the last time they hear anything at all about their own reproductive systems.)
At the same time, we should avoid the mistakes we make with public-health messaging about women and reproductive risk, which tends to lay blame at the feet of individuals and stigmatize those who cannot “achieve” perfect health. Any one person’s health is not solely a matter of individual choices. Health also depends on structural factors, such as access to high-quality and affordable health care; the availability of sidewalks and green spaces and good food to eat, in neighborhoods that are safe; and the cleanliness of the air and the water. And in any case, it is not possible to reduce reproductive risk to zero.
Still, paying more attention to this aspect of men’s health could improve their lives and their children’s lives. It could also reshape our culture and politics more broadly, cutting against default assumptions that reproduction is just a “women’s issue,” and solely women’s responsibility. Bringing men into the frame offers an entirely different picture of reproductive health, of masculinity, and of fatherhood.