Not sure what you're meaning to say exactly... Are you trying to say that girls with brothers are less likely to become sluts? Or, if you were just asking what everyone else thinks:
Just out of curiosity, do you guys a reckon an attractive teenage girl with divorced parents and no brothers makes a likely combination for her to be a slut?
I'm thinking the broken-family aspect there will have some part to play in increasing her chances of becoming a slut (key word being "chances", not "certainty"), but I don't actually think the lack of male presence has much to do with it. ...unless she were a rural homeschooler who hardly knew what a male WAS... then she'd probably have a stronger urge to get associated with one. In fact, it's interesting to note that it's these lonely farm-types who are stereotypically known to have more cases of incest (rednecks come to mind), probably because extended periods of time (like years) with no "male options" makes the minds of some start considering alternatives of who to "get with"... (unless there's some other factor I'm not aware of)
I seriously reckon girls who lack male presence in their family will turn to guys, boyfriends etc, and hence be more sexually active at a younger age.
Well, here's something to consider: it has been suggested that brothers/sisters who share beds and/or bedrooms can develop small amounts of "sexual retardation", meaning they can have slightly less physical attraction to other men/women, because they are already numbed by the ever-present figure of the opposite sex. But that's only from having
very close proximity (and at almost all times), and I've never heard of this proximity-effect reaching outside of this type of situation...
Perhaps someone here knows first-hand something about the effects of going years WITH vs. WITHOUT opposite-sex siblings/people around? Or the effects of sharing a room/bed, and losing some interest in the opposite-sex's figure? It would probably be too gradual for someone to notice like a light flicking on, but who knows...