Along with what everyone else has said, you can flip the question around and ask why isn't there a stereotype of fathers being overprotective of their sons, and the reason is pretty simple - men are expected to be tough, and fathers would typically want their sons to fend for themselves, even at a young age. Women, and especially girls, are not, and dads will typically try to guard their daughter from threats that either their sons wouldn't have to face (i.e. sexual harassment from adults) or that they would just expect their son to be able to face on their own (i.e. getting in a fight with a school bully).
The same dynamic applies to mothers, but I think the unique father-son dynamic that's the result of thousands of years of the man being the head of the household will make that the relationship that's really different from the others, and the father-daughter relationship just looks more different by comparison. I know my mom was extremely protective of me, but I also think that if someone was trying to analyze why, they'd give a generational "he grew up in a city as a millennial, so of course his parents were overly protective" explanation.
I know there's often businesses called ______ and sons.
That makes me wonder if fathers tend to be more strict about son's life choices and their "son being in line" (Jobs, Religion, Political affiliation etc) than they are with daughters.
