NEW YORK (AP) — Scientists say they've located the first well-documented genetic glitch that increases a man's risk of impotence, a step that might someday lead to new treatments.

Most impotence isn't caused by genetics but rather things like obesity, diabetes, heart disease, smoking, drug and alcohol use, stress or anxiety.

But in a study released Monday by the Proceedings of the National Academy of Sciences, researchers say they located a spot in human DNA where genetic variation might boost a man's risk by about 25 percent.

They found statistical evidence for that by looking in the genetic...