But have you heard of the nub theory? If you're looking for the nub theory explained, or want some more ideas on how to tell your little one's gender, you've come to the right place.
The nub theory claims to be a lot more accurate than some of those old wives tales - and says you can even tell the sex of your baby just by looking at your 12 week ultrasound picture. Usually the earliest point you can tell the sex of a baby from a scan is 20 weeks so the quirky theory is popular with those who can't wait to find out if they're having a little girl or a little boy.
What is nub theory?Between 11-13 weeks, all babies are said to have a 'nub' between their legs called the genital tubercle, and according to this theory 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 from the spine, it's a boy - but if it's under that then it's a girl.
Confused? See our pictures below as an example.
Nub theory indicating a girl
The nub isn't pointing up more than 30 degrees from the baby's spine - in fact it's almost horizontal - so believers would say this showed the scan to be a little girl.
Nub theory indicating a boy
The nub is at a much steeper angle upwards from the spine, indicating that this could be a baby boy.
Not convinced? Netmums have reported the following statistics inline with the nub theory:
Going for your scan soon? You'll have to hope for co-operation from your baby as some professionals say the accuracy actually all depends on the angle of the baby. If you can get a picture of them laying down on their side, that should provide you with a good view of the nub.
If you had success using the nub theory then we'd love to know! Leave us a comment below or send us a message on ourFacebook page.