A man that has multiple female partners is considered a stud.
A woman that has multiple male partners is considered a slut.
Women found a loophole - they can fuck around with as many WOMEN as they'd like and NOT be considered a slut by most in society.
This gives men a reason to not take women as seriously as they should, and go around fucking women - from one to the next.
These men won't stick around of course, leaving their sons to grow up with a single female parent.
This boy has no father figure in his life, and is highly likely to grow up to be very feminine.
This also increases the chances of young daughters to grow up to be lesbians, or bisexuals at the very least.

That is all. I was bored.