No, no, it wasn’t caused by any of the modern marvels to counter erectile dysfunction, it was biological evolution ensuring good sex and the consequences thereof, says Dr Bowman. A report at Press Esc:
“As the diameter of the bony pelvis increased over time to permit passage of an infant with a larger cranium, the size of the vaginal canal necessarily also became larger, potentially resulting in a vaginal-penile discrepancy in size,” Dr. Bowman pointed out. “Sexually satisfying coitus requires a satisfactory ‘fit’ for both partners.”
This meant that as humans evolved, men with larger penises fared better through natural selection as they had a better change of having satisfying sexual intercourse and ejaculating, causing more women to become pregnant.