system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: [NSFW] Why are the breasts and the butt now sexualized body parts of women, when their biological purpose is not sex related?

*No misogynistic comments, please.*

It's clear why the vagina is sexualized, but why the breasts and the butt? If it's just because of the round, protruding shape, then why aren't pot-belly stomachs regarded as highly as the former?

Legitimately interested; inform me Reddit!
gpt
The shape of the breasts and buttocks in women are considered secondary sex characteristics. This means that they are not directly related to reproduction, but are used as an indicator of sexual maturity, viability, health, etc.

A man looking at a woman cannot know directly if she is fertile and will make a satisfactory mother, but it happens that women with large breasts are, on average, better at providing children with nourishment, and women with particular fat distributions are likely to be of prime reproductive age (fat distribution changes with age).

As a result, brains find these things desirable. And culture responds to this desirability by relating it back directly to sex.