Older Fathers: Increased risk of having children with autism, schizophrenia
Older fathers: link to autism, schizophrenia.
Posted Jan 28, 2009
My wife, Elizabeth, and I knew about the risks associated with the children of older mothers, with Down syndrome being the most widely recognized. She was tested for whatever was testable while she was pregnant with Henry, and he seemed to be healthy in every respect.
There is, however, no pre-natal test for autism or schizophrenia. And yet the risks are substantial: A 40-year-old man has the same chance of fathering a child with schizophrenia as does a 40-year-old woman of giving birth to a child with Down syndrome.
Why do we know so much about the genetic ailments associated with older mothers, but almost nothing about the diseases associated with older fathers?
In an article I've just written for Scientific American Mind, I note that the number of older fathers is on the rise, meaning the number of children at increased risk for autism and schizophrenia is also on the rise.
Nobody understand why this should be true. A woman's eggs are constructed and stored before she is born. It's reasonable to think that as they age, they might acquire genetic errors that could lead to disease. But sperm are freshly manufactured whenever they're needed; they are not stored. So what could be going on there?
The speculation is that something is going wrong with the so-called spermatogonial cells, the factories that make sperm. It's unclear what is happening, but the situation clearly deserves further research.
And why are older fathers not told of the risks?
That seems wrong to me. Some time ago, I called Charles J. Epstein, past president of the college of medical genetics, and Marilyn C. Jones, the current president, and asked them if they could explain why this don't ask-don't tell policy made sense, especially considering the new findings. "To put it out there every time somebody comes to you for counseling probably engenders more fear than light," Epstein said.
Jones agreed. "Paternal age is usually not addressed in counseling couples of advanced age because there is no simple test to address the risk," she said. "If there is nothing to offer a couple but increasing anxiety, many counselors and physicians do not bring the issue up."
Why then all the fuss about Down syndrome in the children of older women, when the risks for the children of older fathers are about the same? "You bring up Down syndrome, because you get sued if you don't," Epstein said. "And there are options. You can go through prenatal diagnosis, you have the option to terminate."
Epstein points out that the general rate of abnormalities of all kinds in newborns is about 2-4%. So even a 3% risk of schizophrenia in the children of men over 50 is not out of line with other risks. And it sounds less frightening when put this way: A 50-year-old man has a 97% chance of having a child without schizophrenia.
Still, I wish I had known what the risks were before we decided to have children. Would we have gone ahead anyway? That's difficult to say. But at least we would have had all the information we needed to make an intelligent decision.