Late Fatherhood Affects Children's IQ

By Margarita Nahapetyan

Scientists from Australia do not recommend men to delay their fatherhood as, according to their new study, kids of older fathers have low IQs and do not perform well in intelligence tests during infancy and childhood.

Nowadays, it is very common to start planning a family and having children at a later time, and particularly in developed countries. But while the consequences of delivering children at an older age for women are widely discussed, the effects of increased age for fathers have not been established yet. Previously conducted studies suggested that there was a connection between a paternal age (men after 35) and specific health problems in their kids, including birth deformities and cancer, as well as neuro-developmental disorders, such as autism, schizophrenia and dyslexia.

In the current study, the experts analyzed data from IQ tests that were taken by more than 33,000 children. All kids were born in the United States between 1959 and 1965. The tests were performed when the babies were 8 months, 4 years and 7 years of age, and evaluated the participants for their sensory discrimination, hand-eye coordination in addition to reading, spelling and math ability. The results showed that the older the father was, the lower were the scores on the various tests.

On the contrary, the study has discovered that children with older mothers were more likely to have better scores in the same intelligence tests that were aimed to measure and evaluate kid's ability to think and reason. In their statement the researchers wrote that based on the previous evidence, kids with older mothers tend to perform better because they "experience a more nurturing home environment." If this is really the issue, then the study suggests that kids do not experience such benefits in the same way with older dads. The authors also added that the lower scores that were gained by kids with older fathers could also have something to do with mutation.

The team of experts assumes that age-related accumulations of genetic errors in the cells that produce sperm might have to do something with their results. This might explain findings by other research about the increased risks of neuro-psychiatric conditions and bipolar disorder in the kids of older fathers, said John McGrath from the University of Queensland. "Unlike a woman's eggs which are formed when she herself is in the womb, a man's sperm accumulates over his lifetime, which previous studies have suggested can mean increased incidence of mutations in the sperm at an older age," the scientist added.

However, the differences in scores for the children of older and younger dads were not significant, amounting to about 2 IQ points for the child of a father in his 20s to compare with the child of a dad in his 50s. McGrath says that there is not a 100 per cent evidence to claim that men should avoid becoming fathers after a certain age, but, in his opinion, they should consider and have in mind that there are some risks related to the issue.