The Effect of Ambient Temperature on Sperm Quality in a Desert Climate

The global decline in sperm quality remains poorly understood, with limited research on environmental exposures like rising temperatures from climate change. This study explored the association between extreme temperatures and sperm quality, focusing on normal and abnormal sperm parameters. Sperm data from Soroka fertility clinics (2009–2023) were analyzed alongside ambient temperatures from nearby monitoring stations up to 90 days before sample collection. Summer temperatures ranged from 25.3°C to 46.4°C, and winter minimums ranged from 0.1°C to 24.5°C. Directed Acyclic Graphs guided confounder selection for Generalized Additive Mixed Models and Distributed Lag Models, while Mixed-Effect Negative Binomial Regressions compared sperm quality across temperature extremes. Low winter temperatures were significantly associated with reduced motility, with a 5.8% decrease (p < 0.001). Men with abnormal motility, Jewish men, and older men were most affected, showing motility reductions of 3.59%–6.53%. Minimal effects of extreme summer heat were observed, except for a borderline significant 5.92% decrease in motility among men from lower socioeconomic backgrounds. These findings highlight the negative impact of extreme cold on sperm motility, with potential adaptation to summer heat in desert climates. Further research is needed, particularly among vulnerable groups, as climate change increases temperature extremes.