In his 1694 review of magnifying lens technology, “Essai de Dioptrique,” Dutch naturalist Nicolas Hartsoeker included a drawing destined to make a lasting impression on future students of human reproduction. Inside a drop-like form with a long, straight tail is the lower part of a human body, crouched and holding its knees below a large sphere with an open perforation at the top. It’s the most accurate depiction of what sperm was believed to be at the time: containing a full, minuscule human, ready to be implanted and grow in the womb.
It would take more than a century for sperm to get its name — spermatozoa, from the Ancient Greek for “seeds of living beings” — and even longer until its physiology was understood.
Alas, there are no homunculi crammed inside the smallest human cells. Yet recent research in fertility and urology suggests Hartsoeker’s image could work metaphorically: Sperm can be a proxy for the health of the person who produced it, giving insight into far more than fertility.
At a pace of about 1,500 units per second, 300 million per day, and a lifetime production of up to a trillion sperm cells, spermatogenesis is a marvel of abundance. A single ejaculation contains up to 300 million sperm cells each made over two to three months, in a process that starts at puberty and typically ends at death.
Yet for the 11.4% of men in the U.S. (a value in line with global rates) who struggle with some type of infertility the numbers are far lower, with implications that can be broader than reproductive health. “We know that a low sperm count is a biomarker of other things … and that includes current health — we call it comorbidity burden — and future health,” said Paul Turek, the director of the Turek Clinic and an expert of male fertility and health. Metabolic disorders, cardiovascular disease, cancer, especially testicular and prostate: All show correlation with infertility, and particularly low motile sperm count.
In 2025, a study from Copenhagen University looked at the data of nearly 80,000 men who had their semen quality assessed over 50 years, between 1965 and 2015. It found that men with a low motile sperm count (under 5 million) had a life expectancy nearly three years shorter than men with normal sperm count. Further, issues with any sperm quality parameters were found to be positively correlated with all-cause mortality. “[S]ome men with impaired semen quality may experience less healthy ageing than men with better semen quality and could benefit from being identified at the time of semen quality evaluation,” conclude the study authors.
With data like this, Turek, along with a growing number of other men’s health experts have a bold idea: have men routinely undergo a semen analysis, for the sake of fertility and general prevention of disease. “I am trying to propose to the world that we need guy-necologists,” he said, “and that … the semen analysis is the new Pap smear for men.”
As has happened in other areas of testing (think full-body scans, multi-cancer detection tests), the technology and business is developing faster than scientific consensus. The nascent notion that semen analysis could be a helpful biomarker, coupled with a more general increased interest in male fertility, is beginning to attract entrepreneurs in the testing and fertility spaces, with a clutch of companies offering mail-in semen analysis, and even at-home sperm testing. Turek himself is on the advisory boards of at least two fertility companies, Legacy and Future Family, and the co-founder of AlphaSperm, a company offering pre-conception nutritional supplements for men.
But the push to use semen analysis as an entry point into broader male health also draws considerable skepticism from experts on medical testing and public health. “All of this sounds like speculation. And I’m very skeptical about medical practice that is based primarily on speculation,” said Steven Woloshin, a former director of the Office of Disease Prevention at the National Institutes of Health.
Case for semen analysis as good prevention
Semen analysis identifies four measurements: how much semen, sperm concentration, speed of sperm movement, and shape. Together, these parameters reflect a picture of fertility in the first instance, but also of overall health: Turek likes to refer to them as a hand of cards to be played together with an eye toward statistics and probability, rather than individually as gambling.
Low motility, for instance, can indicate high alcohol or marijuana consumption, while low volume can point to issues of obstruction. Morphology is sensitive to several factors (including genetics and environmental). For low sperm count, some of the causes are well known and easily addressable: the most common is varicocele (an enlargement of the veins in the scrotum), while others include taking too many hot baths or wearing overly tight underwear, smoking, sleep deprivation, and certain medications.
But there are cases of infertility that don’t have a clear cause, and that is where using semen analysis as a biomarker would hold the most value, said Turek. While semen analysis may not give granular information about what is wrong, it can raise a flag in the same way that high blood pressure or routine bloodwork does. However, not only do men rarely undergo the test, but when they do, it’s usually in the context of female fertility treatments, which doesn’t necessarily offer the best opportunity to address underlying causes, said James Smith, a professor of urology at the University of California San Francisco, and chief medical officer of semen analysis company Fellow.
It’s only when a couple has been trying to conceive for at least a year (or six months if the mother is over 35) that a semen analysis is typically performed. When the sperm count is low, the couple often moves on to IVF, said Smith, rather than taking the time to visit a man’s health specialist to identify and potentially address the causes of the low count. It takes three months to make new sperm, and from a couple’s perspective “the clock is ticking,” said Smith.
This is also a barrier to research on male fertility. “It’s been difficult to recruit men to some trials,” said Michael Eisenberg, a professor of urology at Stanford. “They don’t want to be randomized to potentially placebo or nothing when they and their partner have been trying [to conceive] for 12, 18 months.”
Further, since low sperm count doesn’t necessarily equal infertility, many men never learn their status anyway.
But if the analysis were done independently from current fertility goals, it could afford men the opportunity to get a sense of their reproductive health, and the time to address any lingering causes of infertility or low sperm count before they are trying to conceive. It could even indicate that they should be monitored for future health conditions, said Turek, or tested for genetic variations that increase cancer risk, such as BRCA.
Unless there were more complex conditions, a primary care doctor could address many of the issues, and would be well positioned to investigate root causes. “I see men in my practice often who are smoking weed, drinking, smoking tobacco, taking testosterone, taking peptides —all sorts of things that are very modifiable, just general health risk factors,” said Smith. “I’m then plugging them into their primary care.”
The added advantage, proponents of this approach believe, is that men would become better acquainted with the health care system: similarly to how women got in the habit of visiting the gynecologist annually to get Pap smears, young men would be lured into the doctor’s office, a place they are known to avoid. “There are a couple of things where younger men will go to the doctor, and if that’s if their penis doesn’t work or their testicles don’t work,” said Smith, whose semen analysis showed him men are increasingly more curious about their fertility.
“It’s always hard to figure out how to motivate people and motivate men,” said Eisenberg, who thinks perhaps getting a sense of their fertility could work as an incentive for men to see doctors, “as a measure of fertility, as a measure of health, maybe as a measure of masculinity.” Like Smith, Eisenberg — who is an adviser to Legacy — reports sensing curiosity among men. “We’ve done studies here at Stanford, and there are men that … want to participate just because they want to know what their semen quality is,” he said.
“We have the opportunity to perform preventative medicine on young men for the first time ever,” said Turek, who two decades ago was a recipient of the first government grant for male fertility specialists and is an adviser to the Men’s Health Network, an organization devoted to closing the lifespan gap between men and women. “We can tell them ‘your sperm count’s low, this is maybe what’s going on: You need to lose weight, you need to kill diabetes, you’re at risk for this, you should get checked for this.’ … This is a golden opportunity that we’ve never had before.”
Case for caution: more doesn’t equal better health
“This whole idea about screenings or health checks … intuitively it makes total sense,” said Barry Kramer, a professor of medicine at Dartmouth and a researcher of overdiagnosis. “But it turns out there’s really no good evidence that health checks in general help make people feel better and live longer,” he said. “Common sense is not a reliable index of usefulness in medicine.”
When it comes to semen analysis in particular, he is skeptical that it would be beneficial when performed at a broad population level. “Non … predicate al mondo ciance,” he said, citing Dante’s “Paradiso” in Italian: Don’t go around preaching nonsense to the world. “In the absence of a particular symptom, you have to really think really hard why you’re doing a test, any test,” he said. When it comes to a semen analysis, he sees it useful as a diagnostic test when a man is facing fertility issues. ”But outside of that context, I don’t know of any reason why you would be doing it,” he said.
Kramer is unconvinced that a semen analysis would be worth doing just to assess a man’s baseline fertility, without thinking about the broader biomarker concept, so that any issues can be addressed ahead of his trying to conceive. “The idea of doing it prophylactically doesn’t make any sense to me,” he said.
“This sounds like a very nonspecific way to address someone’s health profile,” said Woloshin. “I’d sure like to know what the sensitivity and specificity are, and the predictive value of getting a sperm test.” Prior to expanding the scope of any tests — in this case, beyond men who are experiencing fertility problems — it’s essential to assess whether it is reliable and accurate for the intended population, said Woloshin. More importantly, he said, there has to be evidence that it improves outcomes, such as quality of life, overall health, and life expectancy, something that is yet to be proven for semen analysis, given that it hasn’t been performed on a sizable scale so far.
Woloshin brings up an ethical issue, too, raising the threshold these kinds of tests need to clear in order to be considered beneficial: This wouldn’t be something that is done in response to a patient complaint, but upon physician prompting. “The doctor is saying, ‘you may think you’re healthy and you may not recognize the problem, but let me tell you something that I think you should get’,” he said. This can cause distress, misplaced concern, and overdiagnosis: all harms that have to be weighted against the potential benefits provided by the test.
Turek isn’t too concerned about causing undue health concern. In fact, he sees it as potentially helpful. “Patients unfortunately get a little worried, and that’s important because we’d like them to worry because men aren’t immortal,” he said.
But the cascade of tests that may follow a semen analysis that showed low sperm count or other issues has to be considered from an economic point of view, too, said Emmanuel Drabo, a health economist at the Johns Hopkins Bloomberg School of Public Health. “Literature generally tells us that semen analysis could be leveraged in primary care as some sort of a gateway for men’s health, using fertility concerns as some sort of an entry point,” he acknowledged.
Though as promising as semen analysis may be as a biomarker, he said, it may not be the best screening tool. “Are we going to have unnecessary imaging, unnecessary hormonal tests, unnecessary referrals that are due to mildly abnormal semen results?” he said, noting that this would have an impact in terms of health equity, too. “Resources that we divert toward semen testing are resources that we could have used in other areas of health,” he said.
Still, Drabo doesn’t altogether discount the value of introducing semen analysis in absence of specific symptoms. “Public health is not only about treatment of diseases, it’s about prevention,” he said. “There is potential value in anticipating and addressing problems up-front.”
The business of semen analysis
The public health experts STAT spoke with were especially skeptical about the idea that a semen analysis could draw men at scale into the doctor’s office.
It would be “a new test that costs money, takes time, requires the patient to do something it wouldn’t ordinarily do and bring in his sperm for analysis,” said Woloshin.
Indeed, even those who are excited about the potential of expanding the scope of semen analysis point to the logistical challenges the test presents. The gold standard is to test the semen within an hour of ejaculation to get an accurate evaluation. To do so, a patient has typically two options, neither of which is especially comfortable. One is “having the collection process in a strange room in a strange office, and a lot of guys understandably aren’t comfortable with collecting a specimen in that way,” said Charles Jenkins, the product director of Quest Diagnostics women’s and reproductive health. “The other way is to collect it at home and drive it in and then you’re kind of that NASCAR driver trying to make sure that you’re gonna get over the finish line in time,” he said.
Adding to the complexity is the fact that not all labs offer semen analysis, which requires dedicated instruments and expertise but is not reimbursed at a level that makes it worth the investment, so for many patients even finding a lab may require some effort. “There’s a ton of barriers, and that leads to men not doing [semen analyses] very often,” said Smith, who points out that for this reason only 30% of men who had a vasectomy follow it up with a semen analysis to check that it worked, despite it being the recommendation.
Hoping men would overcome such challenges just to get a peek into their fertility may be too optimistic. But even before benefits are unequivocally demonstrated, the interest in making semen analysis more easily accessible is being accompanied by business innovation and growth. Enter mail-in testing, one of the offerings trying to benefit from the growing male infertility market, estimated at $4 billion a year.
Fellow, Smith’s semen analysis company, developed technology that preserves sperm for up to 72 hours, allowing patients to collect samples at home and send them in a package specially developed to maintain their quality. The company, which launched its services in 2020, will test semen to assess fertility for $199, with an option to pay $140 to freeze sperm. Tests can be ordered directly by patients, who then may need to find specialists to interpret them, or by physicians. Legacy, a competitor, offers standard semen analysis for $295, which goes up to $540 for sperm freezing. Jenkins’ lab, which he founded in 2008 as ReproSource then sold to Quest, doesn’t provide direct-to-consumer options, and offers a broader range of fertility testing. Though it, too, processes mail-in samples (its technology keeps them viable for 26 hours).
These labs’ potential client base would grow exponentially, if Turek and other semen analysis enthusiasts — who all have at least some involvement with businesses offering convenient semen analysis solutions — are successful. He is determined to be, as he sees popularizing the test as his contribution to ending what he calls a neglect of male health. “The richest men in America live six years less long than the poorest woman,” he pointed out. “We have a huge life expectancy discrepancy in America, and this is my approach to eliminating it.”
STAT’s coverage of health challenges facing men and boys is supported by Rise Together, a donor advised fund sponsored and administered by National Philanthropic Trust and established by Richard Reeves, founding president of the American Institute for Boys and Men; and by the Boston Foundation. Our financial supporters are not involved in any decisions about our journalism.
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