IF women are biologically programmed to be anything then that's choosy. It just makes more sense to only sleep with attractive men if you can get pregnant - after all, you don't want to go through nine month of pregnancy for a child with a bad immune system.
A slut, in my definition, is a woman who puts up with bad sex (or worse, date rape) in the hopes that she will have fun and/or men will like her. In short, a woman who has fallen for the lies of patriarchy and is insulted by men for her efforts.
And yes ... one could say society encourages such behaviour. Society also encourages rape fantasies. I mean, if the men watch porn, women without rape fantasies wouldn't be sexually compatible, right?
And ... we would KNOW if women were more promiscuous than men. Because that'd mean a lot more lesbians than presently exist. Lots and lots of lesbians. 
As things are, I think it's a safe bet that men are more promiscuous. There are more gay men than lesbian women, and they also are more promiscuous than lesbian women, so ...