Monday, December 08, 2008

Intelligent men have better sperm: research

More evidence that high IQ is usually a sign of greater overall biological fitness. Amusing that this was one piece of research where the small size of the effect was played up

Research has suggested that in our ancestors intelligence and sperm quality were linked so clever men were more likely to reproduce. It is thought that the genes that are linked to intelligence also have a role to play in sperm quality, even if the effect is only small.

But experts said that if couples are having problems conceiving it does not mean the man is not intelligent or that training your brain will improve your chances of becoming a father. In modern society intelligent men actually tend to father fewer children through greater use of contraception and marrying later.

A team at King's College London were testing a theory that single genes can affect a wide range of characteristics that are seemingly unrelated. Ms Rosalind Arden, lead author, said "As an initial proof-of-concept, we took two characteristics that seemed, on the surface, unlikely to be associated with each other- intelligence and sperm quality - and tested whether there was a statistical relationship between them. "We found a small positive relationship: brighter men had better sperm.

"But we are not trying to say that under modern conditions intelligent men are going to have more children. "We wanted to test the idea that intelligence is favoured by natural selection." The effect remained after factors, such as intelligent men being less likely to smoke and more likely to exercise more, were taken into account. The research is published in the Journal Intelligence.

Dr Allan Pacey, Senior Lecturer in Andrology, University of Sheffield, said: "The fact that it's possible to detect a statistical relationship between intelligence and semen quality in adult men probably says more about the co-development of brain and testicles when the man was in his mother's womb, and therefore how well they both function in adult life, rather than suggesting that playing Sudoku can somehow stimulate more sperm to be produced. "The improvement in semen quality with intelligence observed in this paper is small and therefore it is unlikely to have a big impact on the ability of men of different intelligences to conceive." The effect was small so is unlikely to be relevant to individuals, Ms Arden said.

The researchers analysed data from 4,462 former US soldiers who had served during the Vietnam war who took several intelligence tests and underwent a detailed medical examination. Of these, 425 men also provided semen samples. The researchers examined the relationships between intelligence, semen quality which was measured using standard sperm motility, sperm concentration, sperm count tests, age, and the main lifestyle factors known to predict health: obesity body mass index, and use of alcohol, tobacco, marijuana, and hard drugs. The correlations were small but highly statistically significant.

Ms Arden said: "This does not mean that men who prefer Play-Doh to Plato always have poor sperm: the relationship we found was marginal. "We look forward to seeing if the results can be replicated in other data sets, with other measures of intelligence and other measures of physical health that are also strongly related to evolutionary fitness".


Milk a sight for sore eyes

Soon we could be putting milk in our eyes, not just drinking it. Sydney scientists have discovered a protein in milk can help fight drug-resistant bacteria that cause eye infections. It also speeds the healing of wounds to the cornea. And when attached to contact lenses, it prevents bacteria growing on them, reducing the risk of eye disease.

Institute for Eye Research chief scientific officer Mark Willcox said infections of the cornea could lead to blindness within 24 hours if not treated. A common cause of these infections is the pseudomonas aeruginosa bacteria, which releases a substance that "basically gets in the eye and starts to eat it", he said. The bug is found widely in the environment, including swimming pools, and is even responsible for lettuce rotting in the fridge.

Institute researchers found that part of the milk protein, lactoferrin, could enhance the ability of antibiotics to kill drug-resistant strains of the bacteria, which cause serious infections in other parts of the body, including the urinary tract and lungs. While it could take more than five years for lactoferrin-based eye drops to become available, contact lenses impregnated with the milk protein could be on the market within two years, Professor Willcox said.

About one in 500 people a year who sleep while wearing contact lenses develop an eye infection.


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