okay
just adding my two cents as a guy who had great growth (only seen a few guys my size and maybe 1 bigger) and has had metoidoplasty AND phalloplasty, AND has had lots and lots of sex with girls so I think I am qualified to chime in.
First of all, before surgery, I never had a girl complain about my tiny penis. I did have one girl say "that's it?" I laughed it off and said "yup".
Yes some girls want big penises, some girls want small penises (one of my partners said "yes its small so I can savor it" lol whatever) and I think a lot less women care than we guys think. Our confidence about it is a huge part of how our partner deals with it.
I made it up in my mind to be an excellent lover (before I had a decent size penis) and can please a woman very well with things other than my penis. Sex is so much more mental for women (hope that doesnt sound sexist) but making a woman feel sexy and hot and irrestible even with a below average penis, will probably do more for her than completely ignoring her needs with an average or large penis.
Next, I think most guys have a really skewed perspective of what an average size penis is - 5.5 inches is average erect and 3.5 is average flaccid.
As far as my phalloplasty, I am happy with it, I can orgasm, my partners have been satisfied and it passes without question in the locker room.
Any way, I am not sure if t growth is genetic. I was really really fortunate with my growth and I also happen to know that my father was well endowed. Found some photos when I was rifling through my mothers desk as a kid.
But yes we are limited on the amount of growth we get because most of us did not receive the special hormonal bath when we were in the womb. This is the time when things really happen.
The best thing we can do is own what we have and use it to our advantage. Being born with such unique genitals really taught me to do other important things in bed and I am so greatful for that.