Nub theory: Predict your baby's sex at 12 weeks

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Nub theory: Woman holding up a scan picture

Can you tell if your baby is a boy or girl from just 12 weeks? We've all heard of the old wives tales like carrying your baby bump low means it's a boy or if you're craving sweet things, you're expecting a girl.

However, the nub theory claims to be a lot more accurate - and says you can even tell the sex of your baby just by looking at your 12 week ultrasound picture.

What is nub theory?

Between 11-13 weeks, all babies are said to have a 'nub' between their legs, and the angle of the nub will indicate whether it's a boy or girl.

It's said that if the nub is over 30 degrees up, it's a boy - but if it's under that then it's a girl. See our pictures below as an example.


Nub theory - girl picture

Girl nub: The nub isn't pointing up more than 30 degrees - in fact it's almost horizontal!

Nub theory - boy picture

Boy nub: The nub is at a much steeper angle upwards, indicating that this baby is a boy.

Going for your scan soon? You'll have to hope for co-operation from your baby - but if you can get a picture of them laying down on their side, that should provide you with a good view of the nub. 

More boy or girl predictors

- Chinese birth predictor
- Boy or girl quiz

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