Jeremy Grantham says median male sperm count will hit zero by 2045

Jeremy Grantham has called two market bubbles and been right both times. Now he has a new prediction, and it is considerably more disturbing than a dot-com correction. According to researcher Shanna Swan’s data, which Grantham has spent years studying, median male sperm count is on course to hit zero by 2045. Not low. Zero. That is not a typo and it is not a metaphor.

Grantham, the co-founder of GMO and one of the more credible doom-callers in finance, came on Diary of a CEO to explain how a guy famous for managing hundreds of billions of dollars ended up obsessing over sperm. The short answer is that 27 years of environmental research kept pointing him toward the same conclusion: the same chemical contamination that has cut the biomass of flying insects by 50 to 75 percent in sixty years is doing something remarkably similar to human reproductive systems. When you put it that way, the leap from asset allocation to andrology starts to make a grim kind of sense.

From 180 Million to 35, and Falling

The numbers Grantham lays out are genuinely alarming, and the timeline is shorter than you want it to be. In hunter-gatherer populations, he estimates, men averaged around 180 million sperm per milliliter. By the time academics started measuring in 1970, it was around 100 million. Today it is 35. The World Health Organization now estimates that 17 percent of young couples need medical help to conceive, a figure that was effectively zero two decades ago. The threshold for unassisted conception, Grantham says, is roughly 45 million units per milliliter. We blew past that fifteen to twenty years ago.

The decline rate this year is 2 and a half percent a year. You don’t have to be mathematically that literate to realize that a 2.5% decline in your sperm count every year is a disastrous level, a nonsustainable level.

At 2.5 percent annual decline, the math writes itself. Swan’s projection, which Grantham says he reached independently, is that the average young couple will need fertility assistance within 20 to 25 years. By 2045, the median count hits zero. Half the male population with no viable sperm, the other half clinging to the edge. A small percentage, maybe 10 percent of men, will still have counts in a healthy range because the distribution is wide. But the median is the story, and the median is catastrophic.

Dr. Swan’s projection indicates that if the current rate of decline continues unchecked, the median male sperm count is on track to hit zero by 2045.

Plastics, Pesticides, and the Policy Gap No One Talks About

On causes, Grantham and host Steven Bartlett are aligned and thorough: phthalates in cosmetics and food packaging lowering testosterone in male fetuses during the first trimester, BPA flooding the male body with synthetic estrogen, PFAS forever chemicals accumulating in blood and testicular tissue, microplastics physically embedded in human placentas and, per a 2024 study, found in 100 percent of testicular tissue samples tested. Atrazine, the herbicide Bartlett calls the chemical castrator, is the sharpest example: banned in the EU for over two decades, it is still the second most widely used herbicide in the United States, and a peer-reviewed UC Berkeley study found it chemically castrated male frogs at levels below the EPA’s safe drinking threshold, turning 10 percent of them into fully functional females.

The regulatory gap between the US and Europe is where Grantham gets pointed. The EU has banned 1,500 chemicals in cosmetics. The US has banned 11. The EU restricted over 1,300 chemicals in personal care products. The FDA has banned 11. The US allows 85 agricultural pesticides completely prohibited in the EU, China, and Brazil. Grantham notes that the life expectancy gap between the US and Sweden has grown from two years to six years over the past 70 years, and he is willing to bet it will reach eight to ten in another 50. This is not subtle.

If the US wants to put the corporations first, they will have shorter lives.

What To Actually Do

Grantham’s practical advice, aimed especially at pregnant women, is surprisingly focused: skip cosmetics for nine months entirely, and spend whatever you save on organic versions of the dirty dozen fruits and vegetables, the ones where pesticides are absorbed into the structure of the food rather than just coating the surface. Berries, apples, pears, peaches, spinach. He thinks that combination alone could eliminate as much as half of the fertility damage being done. The Harvard and Massachusetts General Hospital studies he cites found a near doubling in sperm count between the men who ate the least pesticide-heavy diet and those who ate the most, and a difference of 68 versus 38 percent successful live births among women at a fertility clinic based on diet alone. Those are not small numbers.

One more thing Grantham raises that most fertility coverage misses entirely: the damage is multigenerational. A woman carries all her eggs from birth, so chemical exposure does not just affect her children. A recent study suggests the harm could carry through many more than the two generations researchers thought they could prove. Get these chemicals impregnated in your system, he says, and your grandchildren pay the price too. At that point, 2045 stops feeling like a distant deadline.