Is Male Fertility Actually Declining?

In 1973, Watergate dominated the headlines. The Supreme Court ruled on Roe v. Wade. And men in North America, Europe, Australia and New Zealand pumped out 99 million little swimmers in every milliliter of semen. Fast-forward to 2011, just 38 years later, and sperm counts had dropped to 47.1 million sperm per milliliter—a decrease of more than half, according to an influential analysis published in 2017 in the journal Human Reproduction Updates.

Headlines rang out, calling this "spermageddon"—a crisis in modern fertility that could spell the end of our ability to reproduce naturally. This sperm decline shows no sign of leveling off, either: if sperm counts continue to decline at this rate, by 2045, we'll have a median sperm count of zero. Yep, zero.

But in May of this year, researchers from Harvard's GenderSci Lab called "not so fast" on panic about the decline of the human race. Sperm counts may vary naturally over time, they said in a blog post, and aren't actually a perfect predictor of male fertility. What's more, these sperm decline theories are being weaponized by the alt-right to promote what they see as "the decline of white male fertility and social status," said Meg Perret from the Harvard GenderSci Lab.

So, are we really facing a sperm crisis, and how worried should we be?

Are we plunging off a fertility cliff?

A group of researchers led by Professor Hagai Levine and Professor Shanna Swan found good cause to freak out in 2017 when they performed a meta-analysis, which is an examination of all relevant studies in a particular area. They looked at the results from 185 studies, which included sperm counts of more than 42,000 men, and saw that between 1973 and 2011, sperm counts had decreased by more than 52.4 percent in Western countries (i.e., USA, Canada, Europe, Australia and New Zealand). If the decline continues, Swan predicted that "most couples may have to use assisted reproduction by 2045."

Swan has gone on to write a book about the decline, called "Count Down: How Our Modern World Is Threatening Sperm Counts, Altering Male and Female Reproductive Development, and Imperiling the Future of the Human Race." It explores the reasons sperm counts are declining, particularly in men in Western countries—lifestyle factors such as obesity and smoking play a role, but so do chemicals that influence our hormones. Some chemicals used in plastics interfere with or mimic the body's sex hormones, particularly testosterone and estrogen. They can make the body think that it doesn't need to produce more hormones, so natural production goes down.

One of these is phthalates, which are used in soft plastics, the kinds our food often comes wrapped in. According to Swan, phthalates particularly affect testosterone levels, which goes on to affect sperm counts. Swan believes that a combination of these chemicals, along with lifestyle factors, are causing men's sperm counts to plummet.

Is more sperm actually better?

This year, a team at the Harvard GenderSci Lab led by Professor Sarah Richardson set out to reanalyze Swan's 2017 study, to see whether this problem is as apocalyptic as it seems. The first thing they note is that when it comes to sperm, more isn't actually better.

"Above a critical threshold—around 40 million/mL—sperm count no longer tracks fertility, since a higher sperm count does not necessarily mean greater fertility," said Marion Boulicault, one of the authors working with the GenderSci Lab team. "And even below 40 million/mL, the relationship isn't straightforward: Even holding other variables fixed, some men with lower sperm counts are more fertile than those with higher sperm counts, for reasons that aren't clear." She noted that some men can conceive easily, while others with the same sperm count can't, or take a lot longer, for complex reasons that aren't yet well understood.

Sperm counts themselves aren't a one-stop fertility predictor.

There are also a bunch of other things that can affect sperm count day to day, like how turned on the guy was before he came and how frequently he is ejaculating. Boulicault said one researcher told her he's seen sperm counts increase from 10 million/mL to 100 million/mL based on just a few weeks of the guy keeping it in his pants.

This isn't to say that sperm counts aren't useful predictors of fertility: When taken in tandem with other measures, like sperm quality, which looks at movement and shape, Boulicault said, they can provide useful information about the ability to conceive. But sperm counts themselves aren't a one-stop fertility predictor.

Counting sperm correctly

Somewhere deep in the World Health Organization's library of publications, there's a guidebook on how to count sperm, which attempts to standardize this difficult process. Knowing how hard it is to get reliable sperm counts, the 2017 meta-analysis authors only used studies that counted sperm with a hemocytometer, which removes some of the variability between different sperm counters. Bear with the technical explanation: When left for too long in a lab, semen dries out, which can increase the concentration of sperm in a sample. If the pipettes used to measure the semen samples aren't wiped properly, it can appear that there is more sperm. Both of these things are more likely when sperm counters have less training, as would have been the case in the early decades of sperm measurements, which may have led to overestimating sperm counts. Because of this effect, the decline in sperm counts may not be as stark as it seems.

What about women?

You can't make an omelet without eggs, and you can't draw conclusions on the human race's ability to reproduce by looking only at sperm counts—that's leaving out one crucial half of the equation. So, what's going on with women?

In her book, Shanna Swan talks about BPAs, which are chemicals used to produce hard plastics. They mimic estrogen, and so are particularly risky to female fertility, although they can also affect men. Professor Richard Sharpe from the Centre for Reproductive Health at the University of Edinburgh said the compound nature of male and female fertility issues makes the problem worse.

Age is just one of a mountain of considerations—finances, career, love life—we need to take into account before we go putting buns in ovens.

"Couples are waiting ever longer to try for a pregnancy, so that often the woman is in her 30s or even 40s," Sharpe said. "By age 35, female fertility in a 'normal woman' is 35 to 40 percent reduced compared with her early 20s, and her fertility continues to decline thereafter—beyond 40, this decline is precipitous. When you add a male partner with a low sperm count into the mix, you can see that achieving a pregnancy is going to take much longer, but for such couples, time is a hugely limiting factor—time is not on their side." For this reason, Sharpe said, the lower sperm counts in men today probably matter more than they used to, when couples typically tried to conceive when the woman was in her early- to mid-20s.

Beware the alt-right

While researchers carry out these studies as objectively as possible, they don't have control over how their research is used by the public. For a blog post on the subject, the GenderSci Lab team dove into alt-right online discourse on 4CHAN, Reddit and Twitter, and found sperm decline commentators asserting that the "feminization" of men via "social pressures" and "political correctness" are harming men's sperm counts and reproductive abilities. The team noted that "throughout this discourse, we found that the alt-right expressed anxiety surrounding shifting population demography, changing cultural norms surrounding reproduction, and what they perceive as the decline of white male fertility and social status."

Perret said many of the comments on these alt-right forums reflect what scholars call "male victim ideology," where the rise of feminism and shifting gender norms are portrayed as threatening to men rather than as giving everyone a lot more choice around how they want their lives to play out.

So how can we best prepare for making babies?

If you do want to maximize your conception chances, the advice that comes out of this research is familiar and easy to follow. Some of the things that may be leading to a decrease in sperm decline are modern lifestyle factors—smoking, obesity and unhealthy diets, to name a few. Naturally enough, then, quitting smoking, maintaining a healthy diet and exercising should help.

To avoid environmental pollutants like phthalates and BPAs, try to eat unprocessed foods that don't come in plastic packaging, which could potentially contaminate what you eat with harmful chemicals. If the science on environmental pollutants doesn't bear out, then you're still doing good things for your health and for the environment.

Objectively, having kids at a younger age, especially for the woman, is going to help your chances of conceiving. But that's just one of a mountain of considerations—finances, career, love life—we need to take into account before we go putting buns in ovens.

Taken together, there is some evidence that male sperm count is decreasing, although the science isn't solid enough to herald an inevitable fertility apocalypse. (The Red Pillers haven't been able to back up their concerns about feminism rendering men infertile, either—surprise, surprise.) So you don't need to worry about spermaggedon quite yet, but it couldn't hurt to ditch the ciggies, junk food and plastic packaging in the meantime.

Your swimmers will thank you for it.