A 2010 study also suggests an increased risk of autism in children born to a couple in which the father is older than 40 and the mother is younger than 30. Further research is needed, however. Men older than 50 are more likely to have babies with certain birth defects, such as the bone growth disorder achondroplasia, due to age-related genetic mutations. The risk of cognitive impairment also might be higher for children of older fathers. In a 2009 study, children born to older men scored slightly lower on tests measuring concentration, memory, reading and reasoning skills through age 7.