http://www.economist.com/node/9218127
At least a college graduate has learned something about long term goals and delayed gratification. There are other ways to learn that, but this is one.
The other thing I would say is that women with more education tend to be more risk averse. I’ve read that they are significantly less likely than poorly educated women to have a child out of wedlock. Again, not saying you need college to learn caution, but it seems to be one way.
Before accepting this statistic, I'd like to know if the marriage rates are similar. Are higher IQ women just shacking up and changing partners every three years?