It has long been known that there is a well-established connection between the age of mothers and complications both for the fetus and the mother.
An information page on the website of the Children s Hospital of Philadelphia provides a useful summary of the relationship of maternal age and the likelihood of problems with the child and mother.
The question of paternal age is less clear. Assumptions that there is no change in sperm quality and birth outcomes have been challenged with mixed results. Some studies have shown little or no correlation between paternal age and birth defects, while others have concluded the opposite.
For example 2007 Kaiser Permanante study published in JAMA Pediatrics concluded that Advanced maternal and paternal ages are independently associated with [autism spectrum disorder] risk.
Now a new study in JAMA Psychiatry provides data that suggest that children of older fathers may have elevated risks of several mental illnesses such as schizophrenia, autism, and ADHD. The study authors from Indiana University and the Karolinska Institute in Stockholm conclude: Advancing paternal age is associated with increased risk of psychiatric and academic morbidity, with the magnitude of the risks being as large or larger than previous estimates. These findings are consistent with the hypothesis that new genetic mutations that occur during spermatogenesis are causally related to offspring morbidity.
ACSH s Dr. Gil Ross comments, While I was not aware of the specifics before, I had some inkling of an association between older sperm and adverse outcomes among progeny, although not as clear to me as with older moms. Perhaps this is so because there is no definitive andropause as there is for women, when reproductive capability is clearly over. This study helps to quantify the extent of potential problems, focusing on psychiatric (or perhaps neurodevelopmental) issues later on. I have no specific advice here, aside from informing older men who are contemplating having children to be aware of the increased risk.