Avoid wearing tight, restrictive underwear. Clothing that holds the testicles too close to the body, where they're heated up, interferes with sperm production. Avoid sitting for long periods of time. Avoid frequent stays in saunas, hot tubs and hot baths. Avoid exposure to lead, zinc, copper or radiation.
Pollutants can affect the quality and production of sperm.
Avoid prolonged periods without sex. Lubricants like petroleum jelly and K-Y Jelly can kill or immobilize sperm. Use a water-based lubricant instead. Take good care of yourself. Infections and illnesses can hamper the production of sperm.