But prominently-displayed genitalia is actually an evolutionary advantage and a possible reason why humans walk on two legs. There is a theory that claims that it's because bipedalism changed how both sexes signal their sexual availability to each other.
First, walking upright instead of on all fours meant that human dongs were suddenly on full display, which cut through all the bullshit when it came to mating. When an early human walked up, dick standing proudly in the breeze, a female knew exactly what his intentions were and could quickly tell him to either f**k off or f**k on.
And sometimes "f**k you, creep!"
For women, though, bipedalism had the opposite effect -- a female's parts are suddenly hidden from view when she's no longer on all fours. That made it harder for males to judge when a woman was ovulating (which is not the case in other primates). This might have encouraged monogamy (since the guy would need to pay closer attention to more subtle sexual cues) but also resulted in a lot more sex.
To play it safe, they would engage in sexual activity all the time, not just during mating season which is what almost every other animal does. It soon ushered in an era of 'round-the-clock pounding that eventually helped our species populate the planet. And then some bastard invented pants and ruined it for everyone.