Come out Virginia, don’t let me wait
You Catholic girls start much too late
aw But sooner or later it comes down to fate
I might as well be the one
Billy Joel, “Only The Good Die Young”

Apparently Billy was going after the wrong Catholic girls:

[On] college students … casual physical encounters or what some have termed “hooking up.” In this article, we examine the impact of both individual and institutional religious involvement on “hooking up” in a national sample of college women (N= 1,000). … Catholic college women are more likely to have “hooked up” while at school than college women with no religious affiliation. Second, conservative Protestant college women are less likely to have “hooked up” while at school than college women with no religious affiliation; however, this difference is mediated or explained by church attendance, which is protective against “hooking up.” Finally, women who attend colleges and universities with a Catholic affiliation are more likely to have hooked up while at school than women who attend academic institutions with no religious affiliation, net of individual-level religious involvement. …

Other work on young women’s sexual activity (Brewster et al. 1998), which shows sharply bifurcated patterns among Catholic women—those with high levels of religious commitment tend to delay sexual activity while those with lower levels of commitment display increased odds of sexual behavior compared to their unaffiliated counterparts. … Contrary to the “moral communities” thesis and to some widespread assumptions, the odds of “hooking up” are actually much higher at religious schools than at secular educational institutions. Upon closer inspection, this pattern is determined entirely by a large Catholic college effect.

I gotta admit, it is not easy to come up with a signaling explanation for this pattern.  Thanks to Alex for the Joel quote.