BEIJING, May 9, 2026 /PRNewswire/ — A major new study has found that South and East Asia dominate patterns of male fertility decline linked to global warming, with the strongest and most consistent evidence coming from India, Pakistan and southern parts of China.
The effects of increased environmental temperatures on male reproductive health include decreased sperm concentration and motility and increased sperm DNA fragmentation, or genetic damage that can hinder fertilization and embryo development.
Male-related factors account for about 50 percent of infertility cases worldwide and the impact of rising ambient heat on sperm parameters has serious consequences in large parts of Asia where total fertility rates are in serious decline.
Results of the study undertaken by the Taiwan IVF Group and Ton Yen General Hospital in Taiwan (China) in collaboration with Stanford University (USA) are being presented at the 2026 Asia-Pacific Initiative on Reproduction (ASPIRE) Congress in Beijing.
Research director and clinical assistant professor at Stanford University, Dr. Jack Yu Jen Huang, MD, PhD, FACOG, said: “Given the sensitivity of spermatogenesis to temperature, even modest increases in ambient temperature could have cumulative effects at the population level over time.
“As global warming accelerates, men’s reproductive health could represent a new climate-sensitive public health issue.”
The testes function optimally at temperatures below the body’s internal heat level, and previous studies have shown that high scrotal or ambient temperatures can harm sperm production.
The latest research explored global trends to reveal comparative data between regions. It is based on a systematic review of international studies on temperature exposure and semen parameter trends between 2000 and 2024. Artificial intelligence algorithms and machine learning tools were applied to extract key variables including geographic regions and semen outcomes.
Dr Huang said studies examining only workplace heat exposure were excluded from the analysis because they reflected localized, job-specific conditions rather than broader climate trends.
“Our results therefore represent temperature effects associated with climate at the population level, including consistent seasonal variations showing poor sperm quality parameters during warmer periods.”
Global temperature trends coupled with lower sperm concentration and motility show that South and East Asia are major hotspots, followed by the Middle East, Europe and North America.
“South and East Asia are likely more affected due to a combination of factors, including higher ambient baseline temperatures and rapid urbanization that contribute to greater cumulative heat stress on spermatogenesis,” Dr. Huang explained.
“With ongoing global warming, chronic heat exposure could have an increasing impact on men’s reproductive health.”
Dr. Huang said potential approaches to solving the problem include:
- increase public awareness of heat exposure and reproductive health;
- encourage protective behaviors;
- expand research integrating climate and reproductive health data; And
- explore clinical and lifestyle interventions to mitigate heat-related effects.
The research team was assisted by research intern Jeffrey Zi Kang Huang from Taipei American School, particularly in the application of artificial intelligence in biomedical research, including AI-assisted data analysis and pattern recognition in global datasets.
“Further longitudinal and mechanistic studies will be important to better define causality and guide interventions,” he added.
The ASPIRE Congress is held at the China National Convention Center in Beijing. More than 3,000 scientists, clinicians, nurses and assisted reproduction counselors from around the world are participating in the congress.
For more information, visit https://www.aspire2026.com
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SOURCE ASPIRE
