But it must be genetic, like nose size, rather than biological like muscle etc.
Everything is based on genes, but there are tens of thousands of steps that occur between the genes and the ‘finished’ adult body. Nose size, dick size, muscularity, height, weight, metabolism, et cetera are all regulated at many stages. You have genes that tell how to build a dick, but the actual building of the dick is carried out by proteins and is affected by hormones, chemicals, availability of building material, you name it.
I was given a 7 incher and a big nose, but a scrawny 120 lbs. body and never even got sexual urges until I was 18. Now that’s weird. Though I had eating, drug, and mental problems mostly during my youth, so this is why I think I never grew. I must’ve had NO testosterone in my system until I started eating and working out at 18.
Puberty is a funny thing, and it is regulated by more than just testosterone. You certainly were outside of the normal range for the onset of puberty, and certainly nutritional status or drugs could have played a role in that.
So, I wonder if I had eaten and been healthy when young if I would have a 12” cock?
No.
Then again, there are naturally huge (body muscle) guys on this site who started with smaller dicks than me.
And there are naturally huge (body muscle) guys on this site who started with bigger dicks than you.
So?
So what?
Anyway how about the VAG?
I assume that you are referring to this question:
What effects the way different vaginas look, i.e. some nice and closed compactly, and others with big lips hanging out? Etc. Is this wear and tear, or genetic?
And that you are actually asking about labia, not vaginas.
From my personal observations, I would say that it has much more to do with genes and much less to do with ‘wear and tear’. I have been with several women who had given birth vaginally to children, and their labia were nice and compact. I have also been with women, both moms and not, who had pronounced labia. I doubt that the intromission of our relatively small penises into a woman’s vagina has any great, long-term effect on her labia.