Older Fathers Less Likely to Have Smart Kids

Mar 10, 2009
Men, who became fathers at older age, produce less intelligent children than their younger counterparts, scientists claim.

The recent study conducted by Australian and US researchers involved data of 33,000 children born in US between 1959 and 1965. Their fathers' age ranged between 15 to 65. John McGrath,a leading author of the study at the Queensland Brain Institute and his colleagues analyzed the results of intelligence tests performed by children at age 8 months, 4 years and 7 years. The findings showed that children fathered by older men did less well on intelligence tests. Other factors like mental health and socio-economic status were taken into account.

Previous studies linked father's age to the risk of developing such health conditions as autism, schizophrenia, dyslexia, epilepsy and dwarfism. Now, there is supporting evidence that father's age is connected to intelligence of the child.

"The results were quite startling as it was thought that the age of the father was less of a concern compared to the age of the mother," John McGrath said. Earlier, several studies showed that older mothers have more intelligent children. However, this seems to be not true for older fathers.

Scientists try to explain this fact by peculiarities of male reproductive system. It is known that male sperm undergoes around 150 divisions at 20s and almost 840 divisions at age 50. The risk of mutations increases with greater number of cell divisions, which may lead to health problems. Thus, older men have more chances of having genetic mutations.
The study was published in the journal Public Library of Science Medicine