In one study, four British universities measured the IQ of 900 11-year-olds
and revisited them 40 years later to see how their lives had moved on.
They found that the brighter girls were less likely to find a man who
wants to marry them, with their chances diminishing dramatically in
direct proportion to their level of intelligence.
For each 16-point rise in their IQ, their marriage prospects fell by 40 per cent.
In contrast, boys’ chances increased by 35 per cent with each 16-point rise. (Qtd. here).
One theory is that men want to marry women who are not as smart as they are. I thus explained to my wife (who has a PhD in microbiology) how lucky she was to find a really smart man. Her response was unprintable in a family blog. Let’s just say that she had an alternative theory of why smart women don’t get married, something about a fish and a bicycle.