from what ive read, i do think that it has something to do with it SLIGHTLY.
proportionally wise, its alot more understandable for a guy who is 6'4 or somethin to have a dick that is above average,
as well as for someone of smaller size, like 5'2 or so to have one of a bit smaller porportion
its more common to see a man who stands 6'4 with a dick thats 8-9 inches, than to see a man who is 5'1 with a 8-9 incher.
although i do also believe that genetics are a big deal about it.
take me for example, im 5'10-6ft and 230 lbs, yet im hung quite above average. and my penis is significantly larger than my fathers. i inherited my great grandfathers genes, he stood 6'4, and from what i heard from my great grandmother, he was hung like a horse.
so idk, it should be tested more thoroughly, because till then we will all only have opinions and theorys.