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The Bump Editors

What's the Chance Baby's Gender Could Be Wrong?

You're stoked for that ultrasound to finally tell you if you're having a boy or girl—but just how accurate are the results?

Second to your pregnancy test saying “pregnant” (yay!), the gender reveal is one of the most exciting moments for expectant parents. Some moms-to-be want to know right away whether it’s a girl or a boy, but most doctors recommend waiting until the anatomical survey, which is done around 20 weeks, since it’s more likely to be accurate by then. At that time, you’ll get an ultrasound, and the technician should be able to tell baby’s gender with about 95 percent accuracy.

However, your doctor could give you more specific odds, depending on how easy or hard it is to see baby’s boy or girl parts. The biggest reason for error is that it’s simply too early for the technician or doctor to see the gender clearly. Very early on, it’s possible for a tailbone to get mistaken for a penis or a bum to resemble a vulva. If that’s the case, your doctor will tell you how sure or unsure they are; for example, they could tell you they’re 80 percent sure it’s a girl, and ask you to come back for another look in a week or two.

If you’ve waited the right amount of time, it may still be hard to tell, depending on the way baby’s positioned. For example, the umbilical cord could be blocking what’s between baby’s legs. (If this happens, you’ll probably find yourself wriggling on the table yelling, “Move, baby!”) But otherwise, your doctor or technician should be able to tell pretty well—maybe even with 100 percent certainty. Just be sure to ask exactly how definitive the prediction is before you start painting the nursery.

Expert: Yvonne Bohn, MD, ob-gyn in private practice in Los Angeles and coauthor of The Mommy Docs’ Ultimate Guide to Pregnancy and Birth

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