Heyyyyyy Can someone help me with nub theory I have been looking over and over can’t figure it out

Baby boy 💙

Don't know about nub theory but going by skull theory I'd say boy.

Boy 💙💙💙

Girl 💖

Girl 💗

In the first pic it looks like the “nub” is risen so looks like a boy but The second pic is making me think that’s part of the leg so I want to say girl 💗

Boy x

girl x