Scientists warn of male reproductive crisis as data shows testosterone halved and air pollution linked to sperm DNA changes

Researchers presented data at a European conference showing a 54% decline in average testosterone levels since 1972 and a separate study linking air pollution to epigenetic changes in sperm.

• Scientists presented findings at the European Society of Human Reproduction and Embryology meeting showing average testosterone levels in men declined by 54% between 1972 and 2019.
• A separate study presented at the same meeting linked exposure to ozone and nitrogen dioxide to changes in sperm DNA methylation, which can affect gene expression.
• Prof Hagai Levine, who led the testosterone analysis, said the decline indicates a "major crisis in male reproductive health."
• Prof Allan Pacey, who was not involved in the air pollution study, said the observed changes are measurable but it is not yet possible to conclude they are clinically meaningful for male infertility.

Latest developments

• Researchers said rising obesity and diabetes, along with possible environmental factors like endocrine-disrupting chemicals and global heating, have contributed to the testosterone decline.
• Scientists called for further investigation and policy responses to address what they described as a male fertility crisis.