A father’s age at the time of conception may affect his child’s social development, according to a new study published in the Journal of the American Academy of Child and Adolescent Psychiatry (JAACAP). And this impact appears to be a result of genetic rather than environmental factors.
The findings show that children born to very young or older fathers — below 25 and over 51 years of age, respectively — showed more prosocial behaviors in early development. However, by the time they reached adolescence, they lagged behind their peers with middle-aged fathers.
These effects were specific to social development and were not observed in relation to maternal age.
For the study, researchers evaluated the social behaviors of twins from preschool to adolescence and found that those whose fathers were either very young or older at conception differed in how they acquired social skills. The findings also may offer insights into how paternal age influences children’s risk of autism and schizophrenia, which has been shown in earlier studies.
“Our study suggests that social skills are a key domain affected by paternal age. What was interesting is that the development of those skills was altered in the offspring of both older as well as very young fathers,” said Magdalena Janecka, Ph.D., a fellow at the Seaver Autism Center for Research and Treatment at Mount Sinai.
“In extreme cases, these effects may contribute to clinical disorders. Our study, however, suggests that they could also be much more subtle.”
Janecka and her co-authors used a UK-based sample of more than 15,000 twins who were followed between the ages of four and 16. To determine whether children’s social skills were affected by how old their father was when they were born, the researchers looked for differences in the developmental patterns of social skills, as well as other behaviors, including conduct and peer problems, hyperactivity, and emotionality.
Separately, they studied whether the impact of paternal age on development was more likely attributable to genetic or environmental factors.
The genetic analysis further revealed that development of social skills was influenced mainly by genetic rather than environmental factors, and that those genetic effects became even more prominent as fathers aged.
“Our results reveal several important aspects of how paternal age at conception may affect offspring,” said Janecka. “We observed those effects in the general population, which suggests children born to very young or older fathers may find social situations more challenging, even if they do not meet the diagnostic criteria for autism.”
“Further, increased importance of genetic factors observed in the offspring of older, but not very young fathers, suggests that there could be different mechanisms behind the effects at these two extremes of paternal age. Although the resulting behavioral profiles in their offspring were similar, the causes could be vastly different.”
The researchers hope to replicate these findings in future studies as well as determine their biological correlates.
“Those developmental differences, if confirmed, are likely traceable to alterations in brain maturation. Identifying neural structures that are affected by paternal age at conception, and seeing how their development differs from the typical patterns, will allow us to better understand the mechanisms behind those effects of paternal age, as well as, likely, autism and schizophrenia,” said Janecka.