Australian researchers found that children born to older fathers did not perform as well as other children on IQ tests during infancy. Conversely, the study showed that children born to older mothers scored higher on the same tests. In developed countries, late childbearing is more common. However, while the effects of late childbearing for women are often discussed, the effects of late childbearing for men are less well known. Recent research has shown that there is a link between fathers having children “at an older age” and children’s health problems, including congenital malformations, cancer and psychiatric conditions such as autism and schizophrenia. Researchers studied IQ test data from 33,437 children born between 1959 and 1965 in the United States. The data were taken at the ages of eight months, four years and seven years and measured their sensory discrimination, hand-eye coordination, reading, spelling and arithmetic skills. The results demonstrated that the older the father, the more likely the child was to have lower scores on each test. Conversely, the older the mother, the higher the child’s cognitive test scores. The researchers issued a statement saying, “Previous researchers have suggested that children with older mothers may perform better because they have a better educational environment; if this is the case, the current study shows that children with older fathers do not have such an advantage.” The researchers said that the occurrence of this situation may be related to genetic mutations, as the possibility of mutations in male sperm increases with age.