A related observation that I've made is that young people sometimes make the mistake of trying to make making themselves attractive in a way that would apply to

A related observation that I've made is that young people sometimes make the mistake of trying to make making themselves attractive in a way that would apply to the opposite sex. As a random example, young women will often wear black fingernail polish, which is on average making them less attractive. It looks like damage, as if they had banged on their fingers with a rock and hurt themselves! Damaged, sick, or injured females are unattractive, but scarred males are more attractive. This is because a woman's health is critical to the health of the offspring, but even a dying old male's sperm can just as good as anyone else's. Scars and physical damage is attractive in men because it indicates that they're a "fighter" and didn't die in the process. Fencing scars on the face were a "thing" for centuries! Not on women though. Only on men. You see these errors get corrected as young men and women grow up, they figure these things out through trial and error. You almost never see any woman over 30 with black fingernails unless they're a lesbian. I think the origin of this is each person knows what they find attractive. If a girl looks at a boy, they know what makes that boy attractive, even if on a subconscious level. When they look in the mirror they see someone "unattractive" because if they're not gay, then someone of the same sex is by definition not attractive to them! Hence they try to "fix" this defect they see by making the person in the mirror attractive again... accidentally copying traits they would like to see in the opposite sex onto themselves. Before mirrors, this would not have occurred in nature, expect perhaps for the rare times someone happened to live next to a very still lake they could observe themselves in regularly.