" there's just not a whole lot of living things that chimps won't put their penis into, given half a chance" said Rachel Williams, lead geneticist.
...
"When you think about it, these findings go a long way towards explaining a wide variety of human sexual behaviors once believed aberrant, but now recognized as unfortunately characteristic of homo sapiens and our most closely related evolutionary cousins."
...
Every attempt to date has provoked only loud screeching from the creature, believed to be either efforts at enticement or moans of pleasure in it's native tongue.

So, it's horny monkeys + hony aliens = human evolution.

I soooooo knew it.