Naturally the black and the white get all the sex, the reason is simple, because they have the biggest penis of all.
Unable to woo girls, Chinese and Indian gather to discuss this matter, they come up with the solution, they started to wear clothes.
At first it was funny, putting animals fur on your bodies look like an act of madness, but soon it becomes a symbol of status, of power, of ability to hunt, and of bravery. More and more people starting to wear clothes.
Soon girls forgot about sex and sex only, they started to judge their mates based on the other abilities.
And thus comes civilization.