Jan. 19, 2012 -- Is my penis too small? That's a question that men aren't likely to ask their friends or sex partners.

But behind the closed doors of a doctor's examining room, it's a common question.

Pediatric urologist Lane S. Palmer, MD, chief of pediatric urology at Cohen Children's Medical Center, New Hyde Park, N.Y., hears it a lot.

"Fathers often will ask it about their sons -- and, while in the office, will ask about themselves," Palmer tells WebMD.

Men worried about their penis size usually have some other excuse for seeing a doctor, says Bruce R. Gilbert, MD, PhD, director of reproductive and sexual medicine at the Smith Institute for Urology in Lake Success, N.Y.

"When they come in for something else, they ask, 'Oh, by the way, I am concerned about the length of my penis,'" Gilbert tells WebMD. "Most are men in the 20-to-40 age group. But some are aged 40 to 50, and some even older men ask."

The vast majority of these men are in for a surprise. Worry about small penis size is common. Abnormally small penis size is not.