A study published in the scientific journal PLOS ONE Tuesday found that a father's age at the time of conception didn't influence his child's intelligence.
According to the authors, previous studies have associated having an older father with certain mental illnesses such as schizophrenia and some conditions believed to be caused by genetic mutations. They reference other studies that have shown genetic mutations have more often come from males rather than females. Therefore, they theorized that higher paternal age might negatively affect intelligence.
The analysis looked at 1898 pairs of same-sex twins, born between 1972 and 1994, and their parents, who participated in the Minnesota Twin Family Study. Like the overall population of Minnesota, the twins had predominantly European ancestry (95 percent). Scientists removed from the study any twins with major birth defects or disabilities.
Scientists found no significant correlation between paternal age and either intelligence or personality in offspring. They write, "We did not find support for our hypothesis that higher paternal age at offspring conception, as an indicator of more new, harmful mutations, would predict lower offspring intelligence."
Children's IQ test scores seemed to correlate to their parents' intelligence levels, with little relation to their fathers' ages when they were conceived.