Linea nigra and baby's gender

I've posted this in OWT as well, but maybe I'll get more answers from preggos here :)

Linea nigra is dark line that usually appears on your pregnant belly, from pubic bone up to belly button or even to sternum ( rib cage)

Now the theory is: if it goes only form your pubic bone to belly button and stops, it's a :XX:
If it continues up to your chest, it's :xy:

Does that work for any of you who already know the gender? Or you remember how it was in your previous pregnancies?

Mine goes only from belly button to my sternum and it's very thin, 2mm and light. I', 30 weeks pg.

With DD1 I remember it was 1cm width and it went in 'girl fashion' lol, from pubic bone to my belly button.

I never had one in any of my pregnancies!

Me neither!

I had one with my girls but I don't really remember one with DS.

had dark ones with my boys and early and a late one but really light with my dd. this time i hardly if at all have one...as i feel like i can see one but am not so sure if i am imagining it or it is really there.....nevertheless so far its either there but super light or not at all...so different to my boys....and cannot exactly remember when it did appear with my girl and bacme obvious.

I have a V V faint one from pubic bone to belly button only. I'm having a boy :)

I've never had one.

Never had one.

I haven't gotten one yet this time, but my previous 3 pregnancies I have had it from my pubic bone up to my belly button. Same every time.

I've never had one.