Quantity, color, presence of infections and blood are noted. The appearance, shape, activity and number of sperm indicate if they are healthy enough for fertility. Men who are extremely overweight have more fertility problems. Smoking has been associated with low sperm count and motility. Avoid drinking alcohol when you're trying to conceive.
Alcohol lowers the production of testosterone, a hormone produced by the testicles.
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.