Originally Posted by Tha Q.

That's not completely correct. What you just stated is an anthropocentric and rather arrogant assertion. Do chimpanzees rationalize the amount of milk a breast can hold? No. Sexuality is probably one of the most primeval and powerful desires we have that's innate. As far as I know, you don't have to be taught to be attracted to someone. It's driven by genes. I agree that shape, size, and a healthy appearance all give rise to someone being "fit for mating", but it's beyond rationalization. We're able to rationalize it because we're people. But, even Birds are drawn to other birds with fewer or no "defects". Humans are related to other primates, genetically speaking. And, from studying other ape species, they've come to certain conclusions. One conclusion is that human behavior doesn't differ much from chimps. And, looking at chimp behavior offers a window into our own past. Also, these adaptations take thousands of years. We're not talking without a lifetime. It's almost completely random. Animals don't "choose" features because they are "better." Certain features happen to be "chosen", thereby, eliminating other features that weren't. That = Natural Selection. There is no "point" to natural selection. It's merely adaptations to environmental pressures. That also means there is no such thing as an "evolutionary ladder." It's a myth.