according to new research ... apparently a man's sperm quality turns out to be a decent indicator of his brain power.
Men who scored high on a battery of intelligence tests boasted high counts of healthy sperm, while low scorers tended to have fewer and more sickly little guys.
This suggests that intelligence might tip off a man's overall health to women looking for a mate with healthy genes, explained University of New Mexico evolutionary psychologist Geoffrey Miller at a recent Harvard University talk.
"It's not necessarily that the same genes are influencing sperm quality and intelligence," he said. Rather, the two traits could be linked through a tangled web of biological and environmental interactions that has evolved to help women pick a mate.
Miller and his colleagues uncovered the apparent sperm-intelligence connection after reanalysing data gathered in 1985 to assess the after-effects of the Vietnam War, particularly exposures to Agent Orange. Of the 4,402 veterans who participated in three days of physical and mental testing, 425 provided sperm samples.
After accounting for factors that could skew the results, such as age, drug use, and abstinence before providing a sample, Miller's team looked for a statistical link between men's sperm counts and motility and their scores on several tests of verbal and arithmetic intelligence.
Though the connections between brains and sperm were "not awesome, they're there and highly significant," Miller said. All things held equal, good sperm and good brains go together.
More interesting papers on this topic can be found on his official webpage. I think his lap-dancers-get-more-tips-when-ovulating paper got the IgNoble prize this year also.
My take on this? I agree that there might be no direct link between intelligence [lets call it I ] and sperm quality [ S ]. The way I see it, men can be divided in 4 types:
- High I and High S
- High I and Low S
- Low I and High S
- Low I and Low S
Of course, in a "natural" world, Individuals with low S will be weeded out by their competitors, therefore leaving individuals of types 1 and 3 in the population with high probability.
In a society of a species which is rapidly developing by replacing natural defenses [fur] with "intelligently made ones" [fur coats], it would have been obviously favorable for females to choose type 1 males over type 3. Heck, type 1 males may have even fooled type 3 males and slept with their wives!
Assuming all the above is true, it is easy to see how the two qualities become indirectly correlated.
And assuming that getting a PhD is correlated with "intelligence" ... well ... you get the title of this post :).