The concentration of sperm in semen, also known as sperm count, has halved in the West since the 1970s, according to a research published in the journal, Human Reproduction Update in 2017.
The authors declared a sperm-centric public health emergency. “This study is an urgent wake-up call for researchers and health authorities around the world to investigate the causes of the sharp ongoing drop in sperm count,” said Dr. Hagai Levine, the study’s lead author, from the Hebrew University of Jerusalem’s Faculty of Medicine, “with the goal of prevention.”
GQ, an American monthly men’s magazine portrayed the decline as an augur of a dystopian future. “Within a generation, men may lose the ability to reproduce entirely,” Daniel Noah Halpern wrote in the magazine last September.
Sperm are the reproductive cells in semen, and they’re produced in the testes. “The testicle is a boiler making sperm constantly,” Paul Turek, a California-based researcher and urologist in men’s infertility, explained. And when sperm are made, they’re like a fine wine — they need to be stored and aged for 72 days before they’re ready to travel.
Once mature, they travel from the testes through a network of tubes that propel them out of the penis during ejaculation, picking up enzymes and other ingredients of semen along the way.
Semen that has at least sperm count of 15 million sperm per milliliter is more likely to fertilize an egg, so that’s the level of concentration fertility doctors want to see in men hoping to have kids.
To get to the egg, sperm have to be able to swim, so movement, or mobility, is another key measure. Men with sperm where at least 40 percent are moving are more likely to be fertile.
The morphology factor comes in. The shape of the sperm matters. They should look just like tadpoles — with little oval heads and long tails. A man’s chance of conceiving is thought to go up the more normal-shaped sperm he has.
But these sperm quality measures also aren’t always predictive of fertility. While a man with no sperm can’t father a child through intercourse, researchers have found some men with relatively low sperm counts can conceive — and others with more abundant sperm can’t.
“I always say normal is 15 million sperm per mL,” Anawalt said. “That means millions of sperm in the ejaculate. But why is it that some men can conceive and other guys with the same numbers don’t conceive? It’s a great mystery what divides those two groups of men.”
But the male fertility doctors, like Anawalt and Turek, said they just haven’t seen this dramatic decline in sperm counts during their years in practice, and they’re not convinced there’s an apocalypse coming.
Scientists’ best guess is that there are a number of changes in how we live that haven’t been good for sperm. Being overweight or obese is associated with poorer semen quality — and we’ve seen rates of overweight and obesity soar over the past several decades. Smoking, stress, sedentary lifestyles, and alcohol and drug use are all also implicated.
“The leading hypothesis is that there has been a vast increase in the number and volume of chemicals that have entered the environment during the last 50 years,” Chavarro said.
Think about it. Much of the food we eat and the everyday objects we use these days are stored in or made using plastics, which contain man-made chemicals. These chemicals are also present in our creams and cosmetics, our household cleaning products, and our drugs and medical devices. They leach into our food and water, into the environment, and into our bodies.
Remember: Sperm take 72 days to mature in the body. After that, the mature sperm wait around to get ejaculated. In men who don’t have sex or ejaculate for a long time, those mature sperm can get funky. So one way to increase your fertility is to … have more sex. But not too much.
“The average healthy 18-year-old can ejaculate every day and recharge in time,” said University of Washington’s Anawalt. But for men in their 30s and beyond, sex two or three times per week is thought to be ideal.
Women will be glad to learn that sex with lots of foreplay is better than a quickie or masturbation when it comes to releasing high-quality sperm. “The longer you wait (to ejaculate), the more sperm come out,” Turek explained.
“Treat your body like a temple,” Turek tells his patients. “Pretend you’re training for a race. You need to take great care of yourself. Eat well. Sleep well. Reduce your stress. Exercise. Eat a heart-healthy diet. Your sperm count can be a biomarker of your health.”
