Why do some girls have vertical navel?

Anonymous
I know men like it, but where is it from?
Can only a plastic abdominal operation cause it?
Is it because of a shape of muscles or a bone stracture?
Why only women have it?
Why is it so rare?
If you know something about it, please share with me
Why do some girls have vertical navel?
Why do some girls have vertical navel?
3 Opinion