Is male fertility really declining? The evidence may have been controversial in the past, but studies continue to find reductions in average sperm counts around the world. Most recently, a November 2022 study confirmed that male fertility is still declining globally. In fact, it indicated that the decline may even be accelerating.

We explain the study, look at past research into male fertility levels, and explore potential reasons behind the decline along with steps you can take to improve your sperm health.

Key takeaways

• A study published in November 2022 confirms that male fertility is still declining in the 21st century. The study found the decline is global and may be accelerating.
• The research builds on previous studies indicating that sperm counts have been decreasing for decades.
• The decline in male fertility may be related to factors including lifestyle habits and exposure to endocrine disruptors.
• Those concerned may be able to improve their fertility on an individual level through lifestyle changes, such as following a healthy diet and quitting smoking.

Previous research found that male fertility may be on the decline

Since 1992, research has suggested a decline in sperm counts. However, the question of whether male fertility is dropping over time has remained somewhat controversial.

A groundbreaking study published in Human Reproduction Update in 2017 reported that sperm counts declined significantly between 1973 and 2011. The research focused on men in North America, Europe, Australia, and New Zealand, and was based on 185 studies of over 40,000 individuals. It found an overall sperm count decline of 50–60% over the previous four decades, and suggested the decline may continue.

Recent research in sperm donors provided additional evidence to back this up. A 2021 study published in Fertility and Sterility examined sperm quality from donors across the United States over a 16-year period. The results found declines in average concentration, sperm motility, and total motile sperm, with reductions in semen quality in every geographic region included in the study.

While these studies focused on Western regions, other research has found similar declines in China as well. A study from 2021 analyzed 111 research articles covering over 320,000 healthy Chinese men between 1981 and 2019. It found declines in both sperm concentration and total sperm counts, indicating that male fertility declines may be a worldwide issue.

New study finds male fertility is still declining in the 21st century

The new study from November 2022, published in Human Reproduction Update, built on the 2017 research from the same team to investigate more recent trends in sperm counts and concentration among men around the world. Using data from studies published from 2014 to 2019, as well as their previously published meta-analysis, the authors based the new research off a total of 223 previous studies.

The data included sperm concentration estimates from semen samples collected from men around the globe between 1973 and 2018. The analysis found significant declines in sperm concentration over that period, with the rate of decline accelerating after the year 2000. Specifically, the study found the decline in sperm concentration increased from 1.16% after 1972 to 2.64% after 2000, a notable finding.

What this means, in layman’s terms? Male fertility is still on the decline, and in fact, it appears that the decline is getting faster.

These findings were also particularly significant because of their global reach. The authors’ previous meta-analysis only reported on sperm decreases in men in North America, Europe, and Australia, because of a lack of data for other areas. This research became the first to reveal a decline in sperm count among men in South and Central America, Asia, and Africa.

The global nature of the findings and the indication that the decline may have accelerated underscores the importance of the study, and the need for further research.

What’s causing the decline in male fertility?

It is unclear exactly why male fertility is declining. The cause may be related to modern lifestyle factors. It’s also likely higher exposures to endocrine disruptors, chemicals in plastics and other substances that interfere with the body’s hormone system, are impacting fertility on a wide scale.

Research indicates the following lifestyle factors may be associated with male fertility issues:

• Smoking, which may impair sperm function, damage sperm DNA, and reduce sperm concentration.
• Alcohol, with higher intakes possibly being linked to lower semen volume and impaired sperm production.
• Drugs like cannabis and cocaine, which may harm sperm function.
• Obesity, which is associated with lower sperm quality, reduced sperm counts, and higher chances of infertility.
• Psychological stress, which may reduce testosterone levels and affect sperm production.
• Diet, with processed meat, coffee, full-fat dairy, sugar, and alcohol being associated with poorer semen quality.
• Activities like bicycling, which increases the temperature of the scrotum and may lead to sperm DNA damage and affect sperm production.
• Insufficient sleep, which may be associated with lower semen volume.
• Older age, which is linked to declines in semen volume and sperm motility.

The study also suggested that any combination of these lifestyle factors may increase their negative effects on male fertility.

In addition, research shows that endocrine disruptors can harm male fertility. Most people come into contact with these chemicals every day in a variety of forms. Common endocrine-disrupting chemicals include: 

• Bisphenol A, which can be found in water bottles, food containers, and other plastic products.
• Phthalates, which are present in children’s toys and plastic wrap.
• Brominated flame retardants, which may be used in clothing and furniture to reduce flammability.
• Triclosan, which can sometimes be found in body wash.
• Chlorpyrifos, an insecticide that can be detected in water, soil, and food.

One of the authors from the 2022 and 2017 studies, Dr. Shanna Swan, hypothesizes that endocrine-disrupting chemicals and microplastics can be blamed for the majority of the decline in sperm count and quality over the years. Her book Count Down: How Our Modern World Is Threatening Sperm Counts, Altering Male and Female Reproductive Development, and Imperiling the Future of the Human Race outlines the research supporting this idea.

Learn more about endocrine disruptors and male fertility.

Why does the decline in sperm count matter?

Of course male fertility decline is of utmost importance for those who want children. Most of the world is experiencing record lows in fertility rates, and infertility is becoming more common, now experienced by close to 1 in 6 heterosexual couples.

But a drop in sperm count and quality is not only an important consideration for conceiving — it serves as a reflection of male fitness as a whole.

Sperm production is influenced by the overall health of the endocrine system, the network of organs and glands that control hormones. Dysfunction of the endocrine system, which could be indicated by a drop in sperm production, may be associated with other, more dangerous or even life-threatening issues, like diabetes and metabolic disease and cancer.

What can men do to preserve or improve their fertility?

Bottom line: There’s likely a worldwide decline in average sperm production. But, you may be able to improve your own chances of conceiving a child with lifestyle changes. Some steps you may want to consider:

• Stop smoking, and drink alcohol only in moderation.
• Eat a healthy diet high in fruits, vegetables, whole grains, fish, and healthy fats, and low in sugar, red meat, trans fats, and processed foods. A diet rich in antioxidants will help protect sperm from the damage of environmental exposure and poor lifestyle.
• Exercise regularly and maintain a healthy weight.
• Get enough quality sleep.
• Limit your use of hot tubs and saunas.
• Check with your doctor about the potential impact of any of your medications on your fertility.
• Reduce exposure to endocrine disruptors, such as pesticides, air pollution, and chemicals present in certain everyday products.
• Take supplements that support male fertility, like vitamin C, folate, and zinc.

When seeking to improve your fertility, it’s helpful to understand your baseline semen parameters to know your starting point. Legacy offers at-home sperm testing kits for a semen evaluation without leaving home. The test analyzes your semen volume and your sperm count, concentration, motility (movement), and morphology (shape), giving you an idea of your fertility and any areas that could be improved.

Since semen quality declines with age, you may also want to consider freezing your sperm to safeguard your fertility. Legacy provides secure, affordable short- and long-term cryostorage options, preserving your sperm until you’re ready to grow your family.