On the marriage markets, virgins have been valuable throughout human history. One can conjecture that this is due to the sexual exclusivity that the husband enjoys. Why? Some claim that rich people care, and thus daughters of rich people will try to remain virgin in order to be eligible for marriage within their class. Poor people cannot afford virgins, and thus do not care, and sexual promiscuity before marriage is common.
All these arguments sound crude, but they reflect the fact that virginity is indeed a trait more common, historically, in the upper class. One consequence is that virginity should be more valued in societies that are more stratified. This is what Fabio Mariani studies using a model with a marriage market where poor girls can move up through love and virginity. This model is capable of explaining the recent decrease of the value of virginity as a consequence of the stronger social stratification (which makes matching across classes more difficult), the increase of female labor market participation (which gives new opportunities for women to strike it rich) and the reduced inequality. Interesting ideas, and I would love to see all this put to data more systematically than through anecdotal evidence.