Question about shape?

I already posted a guessing thread but I have a question. The end of my babies nub seems to be split in a couple spots. What does that mean? Anyone know? Attachment 17300Attachment 17301

I'm just wondering how a nub turns into girl parts? And when the nub disappears?

Embryo Development external genital sex organs - angle of the dangle boy or girl ultrasound gender scan - Baby2see