Quality of a man’s sperm depends on how intelligent he is, and vice versa (2008)

Quality of a man’s sperm depends on how intelligent he is, and vice versa (2008)(economist.com)

85 points by pwrfid 12 years ago | 31 comments

mkl 12 years ago |

The correlation is quite small, but interesting nevertheless. I tried looking for replication studies, but couldn't find any.

Here is the publication in question: http://www.udel.edu/educ/gottfredson/reprints/2009semen.pdf

Here is an addendum trying to explain why it might be the case: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2775227/

dtech 12 years ago |

To get behind the paywall, simply Google the title.

I still don't get how Google doesn't nuke the websites that do this into oblivion...

ivank 12 years ago | |

Google's users don't see the paywall, so why would Google care?

davej 12 years ago | | |

Because google claims to care about the wider web not just its search product. This breaks the web.

tomp 12 years ago | |

Not even that is necessary for The Economist - just copy the URL and open it in an incognito browser mode.

IgorPartola 12 years ago |

Alternative theory: men think with their junk. OK, I'll see myself out...

In all seriousness, it'd be great to see a more thorough study here. I see so many confounding factors. Measuring intelligence is a tough one. Perhaps people more likely to score higher on intelligence tests come from a part of the world where higher sperm counts were selected for genetically. For example, how do sperm counts correlated with the number of cold vs hot days during an average year? Or humidity levels? Or circumcision traditions? Or average penis size? My point is that there are so many factors that go into calculating intelligence and at least to me it seems there are as many factors that affect sperm count that this correlation may be influenced by several other hidden variables.

mkesper 12 years ago |

If this would be true, we'd already live here: https://en.wikipedia.org/wiki/Idiocracy

luxpir 12 years ago | |

Doesn't the standard IQ (I know, I know) bell-curve indicate that the majority of humans are less intelligent than the most intelligent? [1]

I suppose the question is how much less intelligent does the majority have to be for the world to look like Idiocracy? How likely is that to happen, given the communication tech and education options that are emerging?

EDIT: [1] Fair point, riffraff. Actually quite tough for me to rephrase without spending significant time on it (I'm clearly not in the minority...), how about: "the most intelligent humans (by IQ) are naturally in the minority, as with any natural distribution/bell-curve, meaning the 'less intelligent' majority already dominate, as in Idiocracy, and by definition they must always continue to do so". That's a mouthful, but I hope the point is clear enough.

riffraff 12 years ago | | |

I think you should rephrase your first line, as it would seem to me the majority of anything is always less anything than the top. (i.e. half of the people are of below average intelligence)

madengr 12 years ago | | |

In other words, the mean is less than the median.

rjempson 12 years ago | |

I should watch that movie, could be amusing. However I'm not sure I understand what you mean. I don't think the study reached a conclusion as to how many children someone might have, merely that the sperm quality was higher/lower.

diggan 12 years ago | | |

The movie gives the view that dumber people get more kids compared to smart people. So the world will, after a point, contain more dumb people than smart people because they simply breed more.

lmg643 12 years ago |

my understanding is that transmitting intelligence to the next generation requires (a) the presence of whatever genes are responsible for intelligence and (b) the absence of mutations affecting those genes.

it would make sense that the quality of sperm correlates with intelligence, because it would have to be less damaged in order to reliably transmit these attributes. the headline seems to dance around this, perhaps because of the controversy involved.

one unfortunate factor which affects the quality of sperm - paternal age. average number of mutations increase every year. so if you're "thinking" about starting a family, consider that a disincentive to wait.

cm2012 12 years ago |

"They may, for example, be less likely to smoke, more likely to eat healthy foods or to exercise, and so on." I would chalk up the small correlation documented to this. Higher IQ people tend to be higher on the social scale and be healthier in a large variety of ways.

a8da6b0c91d 12 years ago | |

Why would you make that assumption? IQ and sperm quality are probably both impacted by deleterious mutations. I would assume quality in both is measuring mutational load way before I made suppositions about SES.

Houshalter 12 years ago |

This is very significant. If human general intelligence was just a coincidence of runaway sexual selection, then what are the chances of that occurring again on a different planet? How many times have peacocks independently evolved?

PedroBatista 12 years ago |

So i can't still figure it out..

Smart guy --> better sperm or Better sperm --> smart guy

maybe my sperm is telling me something with this question.

mantrax5 12 years ago |

"Quality of a man’s sperm depends on how intelligent he is, and vice versa"

I don't think people know what "depends" means anymore. Especially the "vice versa" part.

That means if you improve the quality of your sperm, as a direct consequence you will become more intelligent, which brings forward all kinds of interesting questions, such as do men really think with their balls?

Machow 12 years ago | |

Agreed. That title made wonder what kind of crazy set of working memory training experiments took place. And I don't even know how they would test things in the other direction...