The excellent piece, by Judith Shulevitz, is generally about the "scary consequences" of older parenthood, and specifically about the greater likelihood of physical and mental disorders that children of older parents face. Shulevitz cites the study of older dads that got a ton of attention earlier this year, establishing that "the number of genetic mutations that can be acquired from a father increases by two every year of his life, and doubles every 16, so that a 36-year-old man is twice as likely as a 20-year-old to bequeath de novo mutations to his children." She also writes about "age-related epigenetic mutations" — how environmental influences, such as age, can impact sperm DNA, and therefore traits in our offspring such as body size and mental capacity:
Sociologists have devoted many man-hours to demonstrating that older parents are richer, smarter and more loving, on the whole, than younger ones. And yet the tragic irony of epigenetics is that the same wised-up, more mature parents have had longer to absorb air-borne pollution, endocrine disruptors, pesticides and herbicides. They may have endured more stress, be it from poverty or overwork or lack of social status. All those assaults on the cells that make sperm DNA can add epimutations to regular mutations.
There's also the question of how much we know (or don't know) about the long-term effects of fertility treatments — treatments that Shulevitz herself underwent when finally trying to have her first baby at the age of 37. As one Columbia University professor puts it, "We keep pulling off these technological marvels without the sober tracking of data you'd want to see before these things become widespread all over the world."
In between all of the excellent science reporting is that lingering, ominous coverline: We have no idea what we're getting into. "A phrase I heard repeatedly during these conversations was 'natural experiment,' " Shulevitz writes. "As in, we're conducting a vast empirical study upon an unthinkably large population: all the babies conceived by older parents, plus those parents, plus their grandparents, who after all have to wait a lot longer than they used to for grandchildren."