You likely know that a woman’s age at conception contributes to the risk for birth defects, especially as she approaches perimenopause and menopause. But a new study in the journal Nature has linked older aged fathers with an increase in genetic mutations that are in turn linked to autism and schizophrenia.
The study was done in Iceland in 78 families who had a diagnosis of autism or schizophrenia. The sequences of their genes were compared to those of 1859 Icelanders from the general population.
The researchers found that older fathers were four times more likely to pass on new mutations as older mothers. For example, a 20-year-old dad passes on average 25 new genetic mutation errors to his child; a 50-year-old passes on about 65.
While most of these mutations are harmless, some are the ones associated with autism and schizophrenia. Cause and affect weren’t absolutely proven for the rise in autism, but it seemed a significant contributor.
This topic will become an increasingly important part of counseling older couples and will require doctors to discuss these risks when women consider egg donation and fertility counseling and family building in general. It’s also important for couples that delay childbearing based on the mother’s age only.