Do men have a biological clock? Should they be haunted by its tick, as women have long been? Should they at least be aware that it exists?
A study released today in the journal Nature (and first reported by Benedict Carey in the New York Times) is the latest in a series of data confirming that the age of a father at conception can affect the mental health of his child.
The study looked specifically at autism and schizophrenia, the two conditions that have most often been linked to genetic changes in older fathers. While not a huge risk for each individual -- the chance of a man age 40 or older having a child with either mutation is about 2 percent -- collectively it could explain the jump in autism diagnoses in recent decades. Experts interviewed by the Times suggested that such mutations may be shown to be responsible for 15 to 30 percent of all cases of autism.
What is new about this data is the specificity with which it tracks the increased likelihood that sperm will mutate over time. As Carey writes:
The research team found that the average child born to a 20-year-old father had 25 random mutations that could be traced to paternal genetic material. The number increased steadily by two mutations a year, reaching 65 mutations for offspring of 40-year-old men. The average number of mutations coming from the mother's side was 15, no matter her age, the study found.
So, what will be the effect of this kind of knowledge? In an essay in the New York Times Magazine back in 2009, I asked exactly that, looking at the already significant evidence that older fathers put children at risk (not just for autism and schizophrenia, but also bipolar disorder, lower IQ and even the odds of being conceived in the first place) and wondering whether these facts would make a dent in long-held cultural assumptions.
"The message to women," I mused, has always been "youare the direct cause of your baby's health" while the message to men was "You, too, could be Tony Randall." But I wondered:
If those underlying assumptions were to change, would all that follows from them change as well? A world in which each man heard his clock tick even a fraction as urgently as each woman could be a very different world indeed. All those silver-haired sex symbols, and balding sugar daddies, and average-Joe divorced guys who are on their second families because they can be while their exes are raising their first set of kids -- what if all of them became, in women's eyes, too darned old?
It certainly hasn't happened in the three years plus since I wrote that. I haven't heard of men racing to sperm banks to save samples for their future, the way young women are reported to be freezing their eggs. And while there is a growing acceptance of women dating men who are younger, I don't think that calculations about sperm health are the reason.
What will it take before men hear a tick tick in the night? Or is our view of age as a mother's problem too ingrained to shift?