Is Sperm Count Decreasing? Here's What Would-Be Parents Should Know

Research has shown that sperm count is declining. Experts discuss what that means and what couples thinking about trying for a baby should know.

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A person who ovulates is often the one who bears the brunt of conception efforts. Ovulation happens once per cycle and determines when a person is fertile. The person contributing sperm, either as a partner or donor, is typically fertile at any time—but not always.

"The sperm is as important as the egg in making a baby," says Zaher Merhi, M.D., a Connecticut-based board-certified reproductive endocrinologist and the founder of Rejuvenating Fertility Center. "We underestimate the sperm."

Studies show that 15 percent of cisgender couples have not conceived after one year of trying, and 10 percent haven't after two years. A 2020 report in The Lancet suggests that infertility in those assigned male at birth is the primary or a contributing cause for infertility in about half of couples where the person trying to conceive is assigned female at birth.

Doctors cannot always determine the cause of infertility, but some research suggests declining sperm count is playing a role. Experts discuss what that means, why it may be happening, and what couples struggling to conceive can do to determine if low sperm count is affecting them.

What's Going on With Sperm Counts?

The research into issues with sperm counts isn't new. In 1992, research published in the BMJ, a peer-reviewed journal put out by the British Medical Association, found that sperm count had declined 50 percent worldwide from 1938 to 1991.

The report raised eyebrows and caught the attention of Shanna Swan, Ph.D., a leading environmental and reproductive epidemiologist and a professor of environmental medicine and public health at the Icahn School of Medicine at Mount Sinai in New York City.

But, as a scientist, she's taught to question research by nature. "I and many in the scientific community were skeptical when we saw this sweeping conclusion based on one study," says Dr. Swan, who recently co-authored Count Down: How Our Modern World Is Threatening Sperm Counts, Altering Male and Female Reproductive Development, and Imperiling the Future of the Human Race.

Dr. Swan conducted her own study and published similar findings in 2000. She was also part of a team that found that sperm count declined 50 to 60 percent between 1973 and 2011. But these studies didn't focus on motile sperm count, or the number of sperm that swim. That's arguably the most critical part of a semen analysis. A sperm's ability to move is important for conception. In 2019, Urology published a study based on semen analysis from nearly 120,000 cisgender men showing motile sperm count had declined 10 percent over 16 years.

Other new research says reports that sperm count decreasing has been overblown and some findings don't properly account for different ethnic and racial groups. But having low sperm count can make a successful pregnancy difficult. Experts say talking about sperm count and its impact on conception can make people aware of possible lifestyle triggers and risk factors in their control and take steps to reduce them.

What Can Affect Sperm Count?

Sperm develops in the testicles, but that's not the only part of a person's anatomy that matters for sperm production. "The whole body plays an important role in reproduction," Dr. Merhi says.

While medical reasons can cause low sperm count, including defects in the tubes that carry sperm, experts point to other factors that may also affect sperm count.

Smoking and excessive alcohol use

It's no secret these habits can affect your health—and that includes fertility. "Smoking can damage sperm," Dr. Mehri notes. Research has linked smoking to decreased sperm density, total sperm counts, and total motile sperm.

And while low to moderate alcohol use is OK, researchers say too much alcohol consumption can lower testosterone levels and sperm production. It can also change the way even a healthy sperm moves.


Radiation therapy to or near reproductive organs can lower testosterone levels and sperm count. Hormone therapy, such as estrogen hormone therapy, can also reduce sperm production.

Environmental factors

Toxins in the products we use, the food we eat, and the air we breathe may also contribute to issues. ​​For example, phthalates are a group of chemicals that make plastics soft and flexible. They also help products retain their scent, absorbency, and color, so you'll find them in personal care products, including body cream and air fresheners. "The phthalates are the chemicals I have been most concerned about because of their ubiquity," Dr. Swan says. "They are everywhere." Dr. Swan adds phthalates can lower testosterone levels, and a 2018 review published in Environmental International suggested phthalates could affect fertility, including sperm count and motility.

Herbicides and pesticides, which can present as occupational hazards to individuals working in agriculture and appear in our food, may also reduce sperm count. A 2014 review in Toxicology Letters noted that occupational exposure to pesticides could affect sperm count and motility.

What to Do About a Low Sperm Count

Having low sperm count does not mean starting a family isn't possible. Healthy and motile sperm can still lead to pregnancy even if one's count is low. And it's also just one part of the fertility puzzle. But experts say those with low sperm count may want to focus on a few things.

Make a few lifestyle changes

A few tweaks to one's lifestyle or products used may increase sperm count. "The sperm takes about three months to come from the testicle to where it is going to be used for pregnancy," says Lauren Bishop, M.D., a New York-based board-certified OB-GYN and reproductive endocrinology/infertility specialist at Columbia University Fertility Center. "It will take about three months to see the change."

Individuals can opt to quit smoking, reduce alcohol consumption, avoid using plastics, research chemicals in products using resources like Environmental Working Group and Clearya, and consume a healthier diet.

Look into medical assistance

If a couple is struggling to conceive, they should alert their OB-GYN, and both people should be evaluated. A semen analysis is often the next step. Dr. Mehri says it's available at most labs. "If the numbers are low, I recommend seeing an infertility specialist or urologist to see what the reason is," he says.

Dr. Bishop says a sperm count over 15 million is typical. If a person has a sperm count between 7 to 15 million, a couple has a better chance of having success using intrauterine insemination (IUI). This procedure involves directly placing sperm into the uterus using a catheter.

Dr. Bishop adds it's possible to conceive with IUI with a sperm count lower than 7 million, but it's less likely. She says, typically, couples in this situation will opt for in vitro fertilization (IVF). "For IVF, we only need one good sperm for each egg," she says. "Therefore, it is possible with even very low sperm counts to conceive with IVF. If there are no sperm seen in a sample, then the couple would need to use donor sperm."

Of course, these treatments are not accessible to everyone because of financial costs. IVF can cost $25,000 with medication. Thankfully there are organizations that provide financial assistance for fertility treatments for people who need it.

Focus on mental health

Dealing with infertility can take a toll on your mental health. In fact, research published in 2012 found that cisgender men experiencing male-factor infertility had more negative emotional responses than peers whose partner was infertile or were part of couples with unexplained infertility. Emotions included a sense of loss, lower self-esteem, and stigma.

Beyond fertility assistance to help couples conceive, mental health resources are also available. It's helpful to speak to a doctor about available resources and find support from a community.

"It's definitely valid for men to feel upset about their fertility issues, and speaking to a therapist or other men who are going through the same challenges can be very helpful," Dr. Bishop says.

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