(Let’s me start by saying i thought this thought was hilarious and am in no way trying to comment on actual differences, but just by actual statistical physical difference)
Hear me out; a lot of Africa was known to travel on foot while hunting/ gathering.
In close to modern time, Africa, and Aborigenes (put in comments if missed some or got something mixed historically), but those are the people I met with the largest dicks! As far as I know, neither groups were primarily dependent on mount animals for survival.
And that’s the correlation to me. Big dicks are uncomfortable while riding mount animals. It hurts.
So my opinion is this (and this is the serious part). None of this is substantiated. I wish just thinking about my dick size compared to the last black dick I saw, subsequently I had the thought while playing RDR2 and consumed an indica blunt
I digress… i believe there is a correlation between parts of the world that depended on mounted transportation and on-foot transportation explains penis size on average
I dunno, I could see it affecting ball size a lot more readily. I’ll admit I have only limited horsemanship experience and the dick didn’t really come into play at the low speeds I endured.
You’d think it would affect breast size a lot too, galloping’s got to be pretty painful for more buxom equestrians.