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.

I've never had one either.

I have carried three babies to term -- two boys and one girl -- and had a line only to my belly button with all three. For me, the major difference with my daughter was that my face and hair always looked nasty (oily and dirty and spotty, ick). Sorry!

I had a line just up to my belly button with both boys, it was darker with DS1 than with DS2.

Thought I would update on here that mine finally did arrive this pregnancy, around 30 weeks, and it goes from my pubes up to my ribs. Don't know the gender of the baby yet.

I had it go all the way up my stomach and fade out just under my rib cage during pregnancy with the boys. Didn't have time to develop with my last pregnancy but it probably would have been the same.

ive never had one either, do they only affect certain skin tones? Or is it just random/genetic?

Not sure about skin tones? I am pretty pale white (Irish/German/Russian ancestry) and I have gotten it every time.

I had it twice out of my 4 full term pregnancies, it went from pubic to belly button and stopped and I have all boys The other times I never noticed a linea nigra