What is the Skull Gender Theory & Does it Work?

When she was pregnant, Michigan mom, Shana D., didn’t want her ob-gyn to tell her the gender of her baby — she wanted to find out another way. “I have always been fascinated by superstition and old wives tales,” she says. “I decided to try the skull theory because it sounded like fun folklore, and kind of witchcrafty. I’m not sure if I did it right, but the test told me I was going to have a boy, and I did!”

What is the skull gender theory?

The skull gender theory, which is very popular on pregnancy message boards, is a way of trying to determine a baby’s gender by observing cranial differences that are based on forensic anthropological findings. 


How do you do it?

In general, male skulls tend to be larger and more robust than female skulls. Using a clear profile image from an early ultrasound scan, see if you can get a good look at any of the following features:

  • The top of the head is generally bigger and blockier in males, rounder and more tapered in females.
  • The curved lines running along the temple are more prominent on males.
  • The cheekbone under the eye ridge is more pronounced on males.
  • The forehead slopes more on males and is more of a cliff-drop on females.
  • The chin is rounder on females, more square on males.
  • The eyebrow arch (or “monkey brow”) is slightly bolder on males and typically nonexistent on females.

Does it really work?

“In adults, the skull is the second most reliable part of the skeleton for sex estimation (after the pelvis),” says Julie Lesnik, PhD, an assistant professor of anthropology at Wayne State University in Detroit, Michigan. “But no biological anthropologist would ever pretend that a neonatal skull could give a reliable sex estimate.”

Sounds pretty concrete, but there’s another way of looking at it, according to

Steve Crawford, author of Old Wives Tales for New Mothers. “Old wives tales are not scientific fact, but they bring people together with one common experience.” So why not grab your ultrasound picture and a few friends and start guessing!

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Photo: Getty