Thursday, May 17, 2007
A bunch of news outlets were recently publishing reports of a study that linked month of conception to a child's IQ. The researchers figured out that the kids conceived in June through August did the most poorly on standardized tests. Although I haven't read the original article, every report I've seen says that pesticide exposure at the time of conception is at fault - the idea pesticide use is typically high in the summer
And, you know, I'm willing to buy that the first three months in utero are pretty critical to a child's neurological development.
But presumably, they just did this by using the kids' birthdays, which would have also been linked to the test scores. So basically, they just have good correlation between date of birth and IQ. I mean, nobody found a way to measure their actual exposure to pesticides in utero, did they?
What I'm getting at, is why did they pick pesticide exposure at conception? It seems like there could be other good correlates: what about pesticide exposure at birth? Or allergen exposure at birth. After all, working backwards, these kids would have been born in March-May: springtime! Don't people get exposed to all sorts of weirdo chemicals as they prepare their gardens? Moms could easily transfer that stuff to their kids. Or maybe the kids are being exposed to pesticides in breast milk during their first summer.
Or maybe it's something else altogether: people alter all sorts of behaviours in the summer. Maybe they eat different stuff. Maybe they're exposed to more smog. Maybe the heat causes stress hormones to be released into the circulation of Moms-to-be.
Who knows? Maybe I need to read the original paper... but for the moment I'm not convinced.
Image from Petteri Sulonen and licensed under cc-by-2.0