The sex ratio on many U.S. campuses is around 60/40 and rising. The NYTimes has an excellent piece on the predictable consequences for dating.
North Carolina, with a student body that is nearly 60 percent female, is just one of many large universities that at times feel eerily like women’s colleges…Needless to say, this puts guys in a position to play the field, and tends to mean that even the ones willing to make a commitment come with storied romantic histories. Rachel Sasser, a senior history major at the table, said that before she and her boyfriend started dating, he had “hooked up with a least five of my friends in my sorority – that I know of.”
Only at the IVYs and universities with engineering schools does the sex ratio tend to even out (no doubt for obvious, albeit politically incorrect reasons), which in itself will have consequences for future sexual mores. A number of universities would like to institute affirmative action for males.