Is the nub theory of gender prediction accurate , or just guesswork ?

[sarahhoping]

checking for the slant of genital nub against the spine at 12 week of pregnancy. How accurate is it ?
does it have any science behind it , or just another fun game of pregnancy ?

You will find sonographers use it so it’s a strong indication but not fool proof. There is always an exception to the rule and low nubs can rise. I used it for both my girls l. I’d say accuracy is around 80% in my experience.

I mentioned it to the woman who did my scan and she rolled her eyes and said it's nonsense.
My SIL likes it though and from my first scan predicted a little girl.
It's a boy.
I don't know if there's any science behind it, but I wouldn't take it too seriously.

There's no evidence for it but was accurate for both of mine!

My sonographer said to take it with a pinch of salt but that it is the only theory of that type that holds any weight at all. She said our nub is pointing towards a girl and was right.

Was right for me !

OP here. It was true for me as well. I have a boy now finally after 38 weeks . :)

Very very accurate if the nub is clear and the person knows how to read them

There is some evidence for it, I found at least 2 research papers that said the sex of a foetus could be predicted from the “genital tubercle angle”. 1999 paper said accuracy was 70.3% at 11 weeks, 98.7% at 12 weeks, and 100% at 13 weeks. A 2011 study also found that it was an accurate way to determine sex and referenced 5 similar studies with varying rates of accuracy (74 -100%).

Basically, there is plenty of evidence to say that it’s highly accurate when done by professionals who know what they’re looking for, but bear in mind that these ultrasounds are being performed to get a clear image of the “nub” and are then being examined by highly trained medical professionals rather than the average sonogropher (no shade to sonogrophers, I just mean that these will be some of the top people in their field)

Accuracy rates will be a lot lower for the average scan as they aren’t looking for a clear shot of the “nub”. Add on that people are guessing based on how the nub appears visually (compared to the studies which are calculating the exact angle) then it’s basically down to a 50/50 guess!

Sorry, I have really rambled on but I found it fascinating and it kind of annoys me when people say there is “no evidence” of something when there clearly is. The evidence just isn’t reflective of the average “nub theory” guess. If you’re interested in the actual research just google “genital tubercle ultrasound” instead of “nub theory”.