What increases a man's risk of infertility?
The number and quality of a man's sperm can be affected by his overall health and lifestyle. Some things that may reduce sperm number and/or quality include:
  • alcohol
  • drugs
  • environmental toxins, including pesticides and lead
  • smoking cigarettes
  • health problems
  • medicines
  • radiation treatment and chemotherapy for cancer
  • age

Source: The National Women's Health Information Center