Is penis size determined by genetics?

Well the title is pretty self-explanatory but, is the penis determined by genetics or is it random? Haha has a test even been done?

Just a little curious.

Both, because genetics is random, no test needed.

As far as I know, no one has ever done a heritability calculation for dick size. My guess would be that in contemporary Western cultures where malnourishment is uncommon, the vast majority of variation in penis size is due to genetic variation (although maybe in-utero environmental variation plays a role, too).