The risk of being infertile in men can be heightened when they are exposed to radiation. Radiation exposure (e.g. X-rays) can lead to a reduction in sperm production. In normal doses, sperm count could eventually return to its normal conditions but with high doses and prolonged exposures to radiation, sperm production can be permanently reduced.
Other environment risks that could heighten the chances of infertility in men are: heavy metal exposure, exposure to industrial chemicals, and overheating the testicles (e.g. sitting for long periods, wearing tight clothing).
