Medical Mysteries

The mystery of the belly button

Written by Fred Hilton

To be an innie or an outie, that is the question

Everyone—at least since Adam and Eve—has a belly button. Even Barbara Eden, who played the hot genie years ago on “I Dream of Jeannie,” has a belly button, although the goody-two-shoes censors at NBC-TV wouldn’t let us see it.

The world of belly buttons is divided into two groups: the innies and the outies.

Most of us have innies. Estimates say 80 percent or more of us are innies, though nobody has really counted.

There is considerable disagreement among belly button experts on what causes an innie and what causes an outie. (When you were a kid, did you dream of being a “belly button expert” when you grew up?)

One school of belly button thought holds that innie/outie determination is made by how the umbilical cord is cut.

“Outies usually occur when more of the umbilical cord is left when it’s cut, leading to more skin left over once it dries out,” says. Most agree that an outie can be caused by an umbilical hernia.

“It has nothing to do with how the umbilical cord was cut or clamped,” says Dr. Daniel McGee, a pediatrician at DeVos Children’s Hospital in Grand Rapids, Michigan. “Most outies are nothing more than extra scar tissue.

The rest are caused by an umbilical hernia, when the stomach muscles don’t fuse together properly after the cord stump falls off, causing abdominal tissues to poke through.

Unless an umbilical hernia doesn’t heal within a year or so, there’s no reason to fix your kid’s outie. It’s just one more thing that makes him stick out in the crowd.”

Another theory holds that the innie belly button is the norm, while an outie is the result of a genetic aberration.

“Needless to say, this theory of natural selection does not enjoy widespread popularity among the outie belly button set,” according to

“There is no scientific evidence to suggest that an outie is genetically preordained, or that an innie is the default setting once the umbilical cord falls off.”

“As babies are growing inside the womb, skin grows around the umbilical cord,” says Dr. Michael Schoenwetter, a Los Angeles pediatrician.

“Some babies grow more skin, which results in an outie, and some grow less, making an innie.”

All of this is good and well, but it still doesn’t explain why we couldn’t see the belly button of the hot genie who starred in “I Dream of Jeannie.”

Sources “Are You an Innie or an Outie?” Wonder of the Day #1209, “What makes an innie an innie? And more belly button mysteries,” by Cari Nierenberg, NBC News, May 16, 2011. “The Cause of ‘Outie’ Belly Buttons,” “Will Your Baby Have an Innie or an Outie?” by Robin Heintz Bratslavsky, NewParent. “Why do Some People Have Innie Belly Buttons While Others Have Outies?”

About the author

Fred Hilton

Fred Hilton spent thirty-six years as the chief public relations officer/spokesman for James Madison University in Virginia and ten years prior as a reporter and editor for The Roanoke Times in Roanoke, Virginia. He is now happily retired in The Villages with his interior designer wife, Leta, their Cadillac Escalade golf cart, and their dog, Paris. (Yes, that makes her Paris Hilton).

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