The quality of sperm is highest in the summer and lowest in the winter according to a new study by scientists at University of Manchester, Queen’s University (Ontario, Canada), and Cryos International (Aarhus, Denmark).The researchers found the same pattern of seasonal variation in the highest quality sperm in two very different climates— De...
“The number of motile sperm per ejaculate also followed a seasonal pattern, even after accounting for temperature, indicating that factors other than heat—such as variation in lifestyle, daylight, or environmental exposures—may influence sperm motility.”
I think this is one very interesting take, as I would have guessed different lifestyle in these seasons a huge factor.