Health 101: Infertility in Men

What may increase a man's risk of infertility?

Many of the same issues that affect a woman's risk of infertility also affect her partner's:

  • Smoking cigarettes. Research shows that cigarettes and tobacco reduce male fertility, likely by reducing semen quality. One recent study found that couples who smoked were more than three times as likely to take more than six months to get pregnant compared to couples who didn't smoke.
  • Excess alcohol and drugs. Moderate drinking is unlikely to impact fertility, but consuming levels that may harm the liver or other organs can make men less fertile by lowering testosterone, shrinking the testicles, causing difficulty getting an erection, and slowing sperm mobility. Certain drugs -- especially steroids used by athletes and bodybuilders -- may affect sperm quality as well. Using cocaine or marijuana may decrease sperm quality and quantity by as much as 50 percent.
  • Obesity. Being significantly overweight can throw off hormones that affect male fertility. One study found that a 20-pound weight gain can increase infertility in men by 10 percent.
  • Sexually transmitted diseases. STDs like chlamydia and gonorrhea (both easily treatable with antibiotics) may lead to damage in the testicles that cause scarring, blocking sperm.
  • Age. Though significantly less of a factor than with women (just look at David Letterman, Paul McCartney, and Jack Nicholson, who all fathered children after they were well into their 50s), age does affect sperm quality. And some research has linked paternal age to conditions like autism in their children.
  • Excess stress. As with women, major life stresses -- like a death in the family, job loss, etc. -- may affect fertility by causing hormonal swings that affect sperm count and libido.

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