Silicon Valley’s Answer to Declining Male Fertility? Sperm Racing.

The average human sperm cell is around 50 microns long, roughly the diameter of a hair or the thickness of a heavy-duty plastic bag. Under a microscope, amid a galaxy of proteins, sugars, dust and dead cells, they look like broken satellites, spinning crazily without direction. The motion is generated by the sperm cell’s long flagellum, which can propel it the length of its body every second. That’s under ideal conditions, when a man has been exercising and eating clean, abstaining from alcohol and cigarettes, steering clear of saunas and any endocrine-disrupting chemicals and, certainly, avoiding androgenic steroids.

So when Felix van der Heiden and Manu Bos examined their samples during a March visit to the San Francisco offices of the biotech start-up Sperm Racing, they were shocked by what they found. To the naked eye, they looked like robust young men, tall and broad-shouldered, with feline eyes and complexions like a Ken doll’s. Back in the Netherlands, Bos had been a sponsored skateboarder and was now an influencer; van der Heiden, under the handle Zeta, had parlayed his handsome face and washboard abs into a career as a looksmaxxer, with over 700,000 followers on TikTok. There was just one problem.

“ His sperm — like 60 percent is dead,” van der Heiden said. “And for me, everything’s dead. Just rotten inside.”

It wasn’t a total surprise, van der Heiden admitted. He’d been doing testosterone replacement therapy and dabbling in selective androgen and estrogen receptor modulators. His bloodwork had been showing low levels of luteinizing hormone, or LH, which tells the testicles to produce testosterone and, indirectly, sperm. If he wanted to have children, he would have to start injecting a peptide called human chorionic gonadotropin, or hCG, which mimics LH, to get his testes back online. “ It just takes time,” he said.

Van der Heiden persuaded the technician to check another slide, and he obliged. The average young man produces 50 million sperm per milliliter of semen. Each slide held enough fluid to contain a few thousand sperm cells. This one had two twitching in it. Bos was not impressed. “His doesn’t work, and mine is almost as bad,” Bos said.

“No, I got two sperms,” van der Heiden replied.

They’d planned on coming to San Francisco and doing a sperm race, hoping to make — what else — video content for their YouTube channel, Dutch Brahs. And they didn’t have 90 days for their sperm to recover. Bos suggested bringing in ringers, though that would run counter to the Sperm Racing ethos.