Since humans first appeared on Earth, the way female beauty was depicted has been dependent on culture and time: short legs, long legs; fat body,skinny body; long hair, short hair; tall, short; big eyes, small eyes; white skin, black skin;...
Today, many girls want a darker tan to be more beautiful, but a few centuries back, having milky-white skin was the main characteristic of a woman’s beauty. What is beautiful today, a few centuries or even decades ago would have been ugly, even gross. A skinny, beauty model today may have been rejected by all males a hundred years ago.
But ideas of physical beauty haven't fluctuated just for women. The concept of beauty regarding males is just as fluctuating and ancient.