Background: Evidence indicates an association between older parents at birth and increased risk for schizophrenia and autism. Patients with schizophrenia and autism and their first-degree relatives have impaired social functioning; hence, impaired social functioning is probably an intermediate phenotype of the illness. This study tested the hypothesis that advanced father's age at birth would be associated with poorer social functioning in the general population. To test this hypothesis, we examined the association between parental age at birth and the social functioning of their adolescent male offspring in a population-based study.
Methods: Subjects were 403486, 16- to 17-year-old Israeli-born male adolescents assessed by the Israeli Draft Board. The effect of parental age on social functioning was assessed in analyses controlling for cognitive functioning, the other parent's age, parental socioeconomic status, birth order, and year of draft board assessment.
Results: Compared with offspring of parents aged 25-29 years, the prevalence of poor social functioning was increased both in offspring of fathers younger than 20 years (odds ratio [OR] = 1.27, 95% confidence interval [CI] = 1.08-1.49) and in offspring of fathers 45 years old (OR = 1.52, 95% CI = 1.43-1.61). Male adolescent children of mothers aged 40 years and above were 1.15 (95% CI = 1.07-1.24) times more likely to have poor social functioning.
Conclusions: These modest associations between parental age and poor social functioning in the general population parallel the associations between parental age and risk for schizophrenia and autism and suggest that the risk pathways between advanced parental age and schizophrenia and autism might, at least partially, include mildly deleterious effects on social functioning.