10 proven sperm killers

Briefs

Why do you think Scots brag about their fertility? “It’s their kilts,” says Dr. Wharton, though he admits the difference between boxers and briefs is usually not great enough to merit a change in sperm count.

“Boxers are better than briefs, if a man’s sperm count is on the low side. But it probably has little effect if the sperm count is normal,” says Dr. Danzer.

However, wearing tight bicycle shorts for an extended period of time is a bad idea as well, Dr. Wharton adds. The more constricted a man’s pants are, the less hospitable an environment he creates for sperm production.

A Party Lifestyle

“Tobacco, alcohol, and marijuana can impair sexual function,” says Dr. Potter, who recommends that his patients limit or avoid all of these when trying to conceive.

Alcohol abuse negatively affects semen quality and production, while cigarette smoking impairs sperm’s motility, according to a 2010 study.

In addition to slowing sperm down, other studies show that cigarette smoking can damage sperm DNA and increase erectile dysfunction.

Marijuana isn’t safe either. Smoking pot has been shown to reduce sperm count, sperm function, and overall male fertility.