system
Given the following post, respond as if you're commenting on Reddit:
human
If the testes are on the outside of the body because they need to be at a temperature lower than the body temperature, how come men living in deserts or other hot climates aren't sterile?
gpt
Sweaty balls. In hot climates your balls can still be lower than body temperature because sweaty balls. Your surface temperature can drop lower than body temperature with the cooling effects of sweat. Hotter balls do result in lower fertility though.