Hugh Hefner famously became a dad in his sixties and generally speaking, men are fathering children at older ages (although only rarely in their retirement!). But are there any health risks for the children of older dads? Recent research has suggested that kids fathered by older men might have an increased risk of birth deformities and other health conditions. And now a new analysis by Australian researchers suggests there might be other, more subtle, problems too.
Led by John McGrath, researchers at the University of Queensland re-analysed data from a study of more than 33,000 children born in the US between 1959 and 1965. This was data from an impressive study called the Collaborative Perinatal Project, which tested every child at 8 months, 4 years and 7 years for a variety of skills, co-ordination and intelligence.
Writing in the journal PloS Medicine this week, the team reanalysed the data to take socioeconomic factors into account – something that had been significantly missing from earlier analyses. So as well as looking at the age of the parents, they also looked at the mother and father’s education levels and income, as well as other factors.
The researchers discovered that after adjusting for these social factors – children of older dads were more likely to have lower scores on the tests, with the exception of one test of physical co-ordination. But, interestingly, they found that the children of older mothers were likely to score more highly in the tests.
True – some researchers have suggested that kids born to older mothers have more nurturing home environment, which might explain their advantage. And this study suggests that it doesn’t hold true for older dads. But, looking for a biological explanation, we also know that men’s sperm can accumulate DNA damage, especially as they get older. The take home message seems to be that we need to try and find new explanations for these observations that take into account both the social factors at work, and the underlying biology – and it’s especially timely as the trend towards older parenthood grows.