In the most comprehensive study to date, researchers have found a 50% decline in the average sperm counts among men in North America, Europe, New Zealand, and Australia.
Fifty percent seems like a lot—and it is. And there’s no sign the decline is slowing, which means that male infertility could become a more common problem in the future. The percentage of patients whose sperm counts are between 0-5 million per milliliter (M/mL) increased from 9 percent to more than 12 percent in the last ten years. Anything below 15 M/mL is “low.”
Many of the studies performed on this subject have been done in men who are sperm donors. Donors are considered already to have high counts. This leads scientists to believe that these trends may be further magnified in the general population.
What happened to all the sperm?
Men today are producing less semen than fifty years ago and that semen has fewer sperm cells in it. The explanations outlined by researchers seem endless: pesticides, obesity, smoking, lead, x-rays, stress, diet, lifestyle changes, the environment, alcohol, endocrine changes, fetal exposure to chemicals, etc.
Because sperm count is the best measure of male fertility, the changes are alarming. However, many couples could avoid the problems they encounter when they attempt to get pregnant if they started trying to conceive just a few years earlier. Recently, both the average age of marriage and the average age of first conception have both dramatically increased.
What are the implications of a fertility decline?
Low sperm counts are a signal that men’s health is heading in a negative direction. Poor sperm health is linked to cardiovascular issues, obesity, cancer and more generally to higher rates of hospitalization and death. While men’s life expectancy is increasing overall thanks to advances in medical care, nutrition and sanitation, it’s entirely possible that the life expectancy could start to drop again someday soon.
One of the most important measures of a nation’s economic health is its Total Fertility Rate (TFR). Societies need to main a health birth rate level in order to sustainably replenish its workforce. TFR is defined as the number of children born per woman. The United Nations maintains an international threshold for 2.1 children per woman as the required number to perpetuate economic growth. In other words, a country’s economic growth may be at risk if its TFR drops below 2.1.
Globally, TFR’s are measured yearly by the United Nations Population Division as well as the World Bank. Low fertility rates can often be balanced out by higher rates of immigration, however maintaining national labor force growth requires both high TFRs and high rates of immigration.
The United States’ TFR has fallen dramatically from 2.1 in 2007 to around 1.8 in 2018, and is expected to continue to decline in the coming years, most likely due to increased use of IUDs, increased expectations of educational attainment, and delayed marriage.
Fertility rates vary widely around the world. A lot of the differences can be explained by anthropology: in other words, culture. People make their decisions about childbearing not just because of their individual pursuits of happiness but also because of how their cultural values shape their behaviors. In some nations, people are more comfortable talking about the idea of birth control; not surprisingly, those countries are more likely to have lower birth rates. And when social attitudes changes, as they do when a nation develops toward the modernity, social behaviors change as well. Political conditions, the spread of specific ideologies, and changes in cultural attitudes matter as much, if not more, than economic disparities.
Here’s a breakdown of why fertility rates are so disarmingly different when filtered through different cultural lenses:
Denmark (Fertility rate: 1.8 children per woman): One of the most economically and socially developed countries in the world, Denmark always ranks highly in the United Nations’ World Happiness Report. In a study of Danish university students, most of the participants stated, unsurprisingly, that they wanted to have children in the future. A clear majority claimed that having a partner to share responsibility with was the most important circumstance for parenthood. However, significantly more men than women first wanted to have completed their studies, to have started a career, and to be in a permanent job position, before having children. Significantly more women found it important to have children before being ‘too old’. The students, however, were unable to identify correctly the age at which a woman’s fertility potential begins to decline most often, often stating that they would like to begin having children at ages past a woman’s prime years for child rearing. This is a pattern seen often throughout many developed countries, including the United States. (Sorensen)
Nigeria (Fertility rate: 5.5 children per woman): Nigeria is the seventh most populous country in the world. with a rapidly increasing population currently sitting around 200.8 million people. The majority of respondents in a study of 202 male Nigerian students studying in the United States agreed that information about family planning, including information about male fertility, was not readily available to men, but that women should not practice family planning without the consent of their husbands. Nigeria has experienced rapid population growth over the last several decades, but many Nigerians do not believe that the population growth is a cause of poverty, poor health, or unemployment. In general, government policies, though supported by the Nigerian population, based on female fertility were not able to solve the population boom in Nigeria. Maybe it’s time for the attention to turn to male fertility practices? (Adamchak)
China (Fertility rate: 1.6 children per woman): In 2015, China ended its one child only policy which had been in place for nearly five decades. A 2009 survey of 4600 women throughout China had made it apparent that the population decline, in which over 400 million births were prevented, may create increasingly serious problems in the future. As in the United States, factors that decrease a woman’s willingness to have children include young age, high income, high education level, urban location, and good employment. As the country’s population continues to age, difficulties in sustainable development will echo throughout the world, as a nation’s fertility rate is closely tied with their ability to develop economically. (Cao)
India (Fertility rate: 2.3 children per woman): According to experts, Fertility in India is often characterized by gender-based stigmas that without children, women do not serve a purpose. Women are often uneducated, so their only identity comes from being a mother. Infertile women are ostracized from society for “draining joy” from the room. In fact, one woman stated that without children, “People don’t know what to talk to you about.” In the Hindu religion, a woman without a child, particularly a son, cannot even go to heaven, leaving infertile couples to wonder who will bury and mourn for them. Infertile couples don’t publicize the fact that they need help even if they can afford treatment. Children are seen as gifts from the gods, so failure to conceive may be perceived as an indication that someone has sinned or is unworthy. On the male side of the equation, significant declines in sperm count, quality, and motility have been found in Indian men over the last 37 years. There has been a downward trend in important semen parameters such as concentration, motility, and normal morphology of the sperm, though the causes are unknown and require further research. (Springen)
Sub-Saharan Africa (Fertility rate: 5.8 children per woman): Millions of people in Africa, especially those in low-resources settings, suffer from unusually high rates of infertility in conjunction with high rates of fertility, a paradox known as “barrenness amid plenty” that accounts for explosive population growth as well as high rates of miscarriage and infant mortality. Despite its prevalence, infertility is also highly stigmatized in this region. Male infertility remains a ‘hidden’ reproductive health condition, even though it contributes to more than half of all cases in the region. In Chad, a proverb states, “A woman without children is like a tree without leaves.” If a woman doesn’t bear children, their husbands have society’s blessing to leave them or take new wives. As a result, women with infertile husbands are often mistakenly blamed for the childlessness. The lack of infertility treatment services in the region, though significantly increasing in the past decade, is often justified as a “form of population control.” (Inhorn)
Middle East (Fertility rate: 2.0 children per woman): One of the most profoundly embedded social trends in the Middle East is consanguineous marriages: marriages of “blood related” men and women. Between 50-80% of all Middle East marriages were consanguineous due to the social and economic advantages they pose: relative ease in finding a partner, strengthened family ties, and better extended family relationships. However, fertility patterns of consanguineous parents demonstrate risk of high infertility, especially among women. Though premarital screening has become much more common in the region, about 90% of couples choose to proceed with their marriages despite the risks identified during screening (such as sickle cell disease). On a different note, countries in the Middle East are ranked among the first nations in terms of high obesity rates. In some countries, such as Kuwait, close to 60% of people are considered obese. The high prevalence of obesity has been associated with a high increased risk of infertility due to hormone abnormalities and genital dysfunction. (Bosdou)
Japan (Fertility rate: 1.4 children per woman): Considered one of the most highly developed countries in the world, Japan is projected to lose two thirds of its population in the next hundred years, should fertility rates continue as they stand today. This puts the Japanese economy and culture at risk for major international decline. Most of the impact stems from the increasing age of marriage, increasing average life expectancy, and overall decrease in marriage rates. Japanese women are expected to marry someone above their own social status, and as Japanese women become more educated, they find themselves in a smaller marriage pool. Japanese men, on the other hand, are expected to both be active in child development but also completely devoted to their work. These mixed messages have resulted in contradictions between the government and the national work culture. (Christiansen)
The international decline in fertility, most notably in the case of Japan, provokes many questions for scientists, sociologists, humanitarians, and researchers alike: What happens to culture when there are fewer children to pass it on? Who will continue to sustain and develop the international economy? What is lost in social structure when opportunities for childbearing pass? Much research, though indicating that sperm counts continue to fall, show signs of hope, that this decline is not permanent. The next step is to figure out why: why such a substantial drop truly occurred, and why no one outside of the scientific community seems to know that this problem is occurring. Only then can large-scale, precise, and effective policy solutions begin to be developed.