I don't think it's so much about breasts as it is about anything that differentiates the typical female appearance from the typical male appearance. Breasts are visually interesting, as are shaved legs, the female genitalia, etc - anything that conforms to the standard feminine appearance.
I'm not sure how it would work out if we switched things up, for example if men were the ones who shaved and women got hairy. Or if all men started growing man-boobs. Maybe we'd be more attracted to hairy women and women would be more attracted to hairless guys with boobs? Then again, females don't put so much emphasis on appearance, from what I gather.
But the part of a woman's appearance that most attracts me is none of these things. To me the face and the eyes are by far a women's best features. Which is odd given that in many situations I tend to avoid looking people in the eye.
hale_bopp wrote:
Someone told me it's partly because you never get to see them very often.. as in public they're covered up.. could this contribute?
Oh yeah, definitely. Makes you wonder what we'd look at if we just all went naked, doesn't it? Maybe we'd be turned off by nakedness and become more attracted to clothed people.