Obviously it doesn't work that way in marriage but im talking about in high school, college and then up until your 25 years old.
Most Helpful Girl
This doesn't apply to all girls of course, I personally don't go for looks.0
Most Helpful Guy
The pickiness of girls helps to make sure they get the best DNA possible to be the father of their children. Whereas even with men having the lower standards we have, more often fail to reproduce at all. Meaning that in order to help men not miss out on our chance to reproduce, men have evolved to be far less picky about who we are attracted to.
Guys are generally attracted to the body parts of the girl, more often than we are attracted to the actual girl. Women on the other hand will be attracted to the guy, and not just his body parts. For this reason women are pickier than guys.
Guys find the female body more beautiful than girls find the male body to be. As a result it takes an exceptionally attractive guy to be as attractive to a woman, that an average woman would be to a guy. This is also why most girls consider anything below a 7 to be an insult. These women consider anything below a 7 to be unattractive in men, and assume it works the same way with our standards.
Once a woman hits 25, her looks start to go, and she often already has kids. At this point she becomes more desperate for a committed partner. Then she will settle for a less attractive male, to raise the children of the men that she really wanted to be with, but didn't want her, because he was too busy having sex with other women. During this time the other 80% of guys have a small window of opportunity to impregnate the female.1