A wide range of disorders and problems in school-age children have been linked to delayed fatherhood. Increased rates of autism, attention deficit hyperactivity disorder (ADHD), bipolar disorder, schizophrenia, suicide attempts and substance abuse problems were all reported.
The studyThe study, in JAMA Psychiatry, suggests mutated sperm were to blame. However, experts say the benefits older dads bring may outweigh any problems. The investigation by Indiana University, in the US, and Sweden's Karolinska Institute has been described as the largest and one of the best designed studies on the issue. The researchers looked at 2.6 million people and at the difference between siblings born to the same father as it accounts for differences in upbringing between families.
ComparingComparing children of a 45-year-old dad to those of a 24-year-old father it indicated:
- autism was more than three times as likely
- a 13-fold increased risk of ADHD
- double the risk of a psychotic disorder
- 25 times more likely to have bipolar disorder
- 2.5 times more likely to have suicidal behaviour or problems with drugs
- lower scores at school
There was no starting point after which the risk started to increase. Rather any increase in age had an associated increase in risk.However, the overall risk is likely to remain low. The problem is small increases in risk scaled up over millions of people having children later. It can lead to an increased incidence of such disorders.