If a man has been unsuccessful at fathering a child, he’ll probably be checked for two kinds of problems: low sperm count (too few sperm per given volume of semen) and poor sperm motility (sperm that are poor swimmers and have trouble fertilizing an egg).
Factors that can reduce fertility in men:
Extreme overweight
Heavy smoking. (Smoking has been associated with low sperm count and poor sperm motility.)
Drug and alcohol use. (Marijuana and alcohol lower production of testosterone, a hormone produced by the testicles.)
Wearing tight, restrictive underwear. (Clothing that holds the testicles too close to the body heats them up and thus interferes with sperm production, which is temperature sensitive.)
Work that requires you to sit for long periods of time
Frequent use of saunas or hot tubs
Prolonged occupational exposure to lead, zinc, copper, or radiation. (Pollutants can disrupt the production, quality, and transportation of sperm.)
Prolonged abstinence from sex
Use of lubricants may reduce sperm mobility.
Infection or other illness. (These hamper the testicles’ ability to produce sperm.)
A varicocele (a congenital defect in the blood vessels to the testes)
For many men, restoring fertility is simply a matter of switching to boxer shorts, quitting smoking, losing weight, or making other adjustments. Be patient, though. It may take two or three months to restore fertility. If you and your partner still don’t conceive, see a doctor who specializes in treating infertility.