Studies have shown that certain environmental factors can have negative effects on male fertility. Overexposure to these factors, such as toxic chemicals or heat, can reduce sperm function and/or production. However, it is important to note that many of these studies are controversial and inconclusive, and there is much more research to be done in this field.
Heat
If the testicles are overheated, it can impair both sperm production and function. This can include wearing tight clothing, sitting for long periods of time, or overuse of a sauna. These factors will usually cause only temporary effects on one’s fertility.
Radiation
High doses of radiation, significantly higher than that of a typical x-ray or CT scan, have been shown to temporarily affect sperm cells. The effects of lower doses are less understood, however, some studies have claimed that there is a correlation between prolonged exposure to mobile phone radiation and a decrease in sperm motility.
Industrial Chemicals
Exposure to chemicals such as organic solvents, pesticides, and paint materials may cause lower sperm counts.
Heavy metal
Exposure to heavy metals such as lead has been proven to correlate with decreased sperm motility and an increase in morphological abnormalities. Males working in the metal industry, with increased blood and semen lead levels, have decreased fertility relative to their peers working in other industries.