Sperm production or function can be affected by overexposure to certain environmental elements, including:
Extended exposure to benzenes, toluene, xylene, herbicides, pesticides, organic solvents, painting materials and lead might contribute to low sperm counts. Exposure to lead or other heavy metals also can cause infertility.
Radiation or x-rays
Exposure to radiation can reduce sperm production. It can take several years for sperm production to return to normal. With high doses of radiation, sperm production can be permanently reduced. It is being reported that keeping mobile phones in the pocket, close to the upper thigh, is extremely deleterious to sperm production with resulting low sperm count and morphology.