men and women unconciously look for traits in each other that will give an offspring the best chance of survival. our enviroment has changed so that the traits women seek are non-physical, like wealth and status. but what men look for in women is still physical. again, those things are youthful traits.
men unconciously look for traits that seem as young as possible. women at 20 have a 1 in 20000 chance of producing a baby with down syndrom. women at 30 or 35 have a 1 in 2000 chance. this explains why men have evolved to look for that.