Male infertility crisis

The male infertility crisis is an increase in

This decline in male fertility is the subject of research and debate. Proposed explanations include lifestyle factors, such as changes in diet and physical activity levels, and increased exposure to endocrine disrupting chemicals, such as those found in plastics and pesticides.^[6][7] Some scientists^[8][9] have questioned the extent of the crisis; the scientific community, however, generally acknowledges increasing male infertility as a men's-health issue.^[10]

Media coverage and terminology

The term male fertility crisis dates to the 1970s.

The World Health Organization published its first laboratory manual for semen analysis in 1980, which sets global standard parameters for the measurement of sperm quality and normality.^[20] Limited research in the 1980s found the first indications behind the decline, with links to environmental-toxin exposure and excessive heat in the genital area.^[19]

1990s–2000s

The 1990s saw significant development in research on male infertility, with reliable results indicating a decline. A 1992 Danish meta-analysis, commonly known as the Carlsen study after its principal author, showed that between 1938 and 1990 a population described as healthy had experienced a significant decrease in sperm count and semen volume.^[21][22] Following this study, other studies supported this thesis. During the late 1990s, the first studies of the social and psychological impact of male infertility were published.^[23] Near the end of the decade, the conception technique of intracytoplasmic sperm injection (ICSI, similar to in vitro fertilisation) was introduced.^[24]

2010s–present

By the 2010s, it was clear that there had been a significant, steady decline in sperm count and semen volume. A 2017 meta-analysis led by Hagai Levine from the Hebrew University reported decreases in sperm concentration of 52.4 percent and in sperm count of 59.3 percent, from 1973 to 2011 in Western countries (Australia, New Zealand, Europe, and North America).^[25] Two other studies presented at the 2018 American Society for Reproductive Medicine (ASRM) scientific congress had similar findings: reduced sperm counts and motility during the 2000s.^[11] A 2012 paper published by French researchers and Yeshiva University's Institute for Public Health Sciences in the Journal of Human Reproduction studied French males from 1989 to 2005 and concluded that sperm counts and the proportion of normal, motile sperm fell by 32.2 and 8.1 percent, respectively.^[26][27]

Mt. Sinai Medical School epidemiologist Shanna Swan wrote in her 2021 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, "If you look at the curve on sperm count and project it forward – which is always risky – it reaches zero in 2045".^[28]

Another meta-analysis in 2022, again led by Hagai Levine, reported that sperm concentration declined by 53.3 percent and sperm count by 56.3 percent in Western countries (1973-2015), and by 27.6 and 24.7 percent respectively, in non-Western countries (1986-2018).^[5] Moreover, when the dataset was restricted to more recent studies (post-2000), the declines in semen parameters became steeper. For instance, the decline in worldwide sperm concentration doubled, suggesting that these declines may be accelerating.^[5]

A 2022 review by prominent researchers in the field of human fertility suggested that increasing industrialisation over the 20th century has led to an increase in exposure to endocrine disrupting chemicals, which may have contributed to the decline in sperm counts.^[6] Other research published in 2023 has linked the change in diet associated with industrialisation, termed the nutrition transition, to declining sperm counts, estimating that the transition from an unprocessed to modern processed diet may account for up to 30 percent of the decline in sperm counts.^[7]

Impacts and responses

Male fertility issues have been overlooked in the past,^[29][30] and fertility research has focused on women.^[23] Sociologists studying male infertility have found that awareness has shifted societal attitudes on fertility and gender more toward men.^[29]

Believers that male infertility has reached crisis proportions say that more must be done to remediate potential causes of male infertility, such as lifestyle factors and exposure to toxic environmental chemicals.^[31][10] They advocate modernizing health care with improved practices and increased funding.^[32]

Social programs to alleviate the impact of the crisis have been implemented as part of men's reproductive health. Events such as International Men's Health Week and Movember advocate reforms to address the crisis.^[33][34]

The Australian federal government funded the Healthy Male, a program to support male reproductive health and fertility, and issued a A$3 million research grant to Andrology Australia.^[35] Other national-government responses include recommendations by the UK's National Health Service for a healthy lifestyle and loose-fitting underwear to improve fertility.^[36]

Criticism

Critics of labeling male infertility a crisis have cited research which has partially stigmatized men, and say that male infertility has inadvertently been conflated with mental health and social vulnerability. However, no direct evidence supports such stigmatization.^[37] Gannon et al. wrote in 2004 that media coverage of the crisis has posed it as a threat to hegemonic masculinity.^[12]

Scientists disagree on the impact of observed fertility declines to date, and sperm counts remain above the 15 million considered to be below normal by the

Andrologists have said that not enough research has been conducted on male fertility to address the crisis effectively.^[40] Existing treatments, such as assisted reproductive technology, are difficult to access and may have severe complications.^[41]

See also

• Sub-replacement fertility
• Ovum quality
• Semen quality

References