Nub theory?

[Ru14]

Anyone ever had any success predicting gender with the nub theory? I don't really get it. This is my 12week scan with my second baby. My sons scan was done at 10weeks so no visible nub to test the theory against!

I wouldn't read much into it. At my 12 weeks scan there was just 1 line and so everyone told me it was a boy. At my 20 week scan I was told he was in fact a she and there were 3 lines visible by that point.