Hard on the heels of worries about BPA in cans and bottles, the University of Rochester Medical Center made waves last week with a study on the potentially feminizing effects of phthalates. Here’s the money sentence of the release: “A study of 145 preschool children reports, for the first time, that when the concentrations of two common phthalates in mothers’ prenatal urine are elevated their sons are less likely to play with male-typical toys and games, such as trucks and play fighting.”
Great! So phthalates, which are found everywhere, in plastics, in food, in your body, everywhere, are going to give us girlie-boys? Not so fast, study lead author Shanna H. Swan: Forbes.com contributor Trevor Butterworth has seen you before. He points out that Shanna Swan has been a prominent voice in the recent rise of worries over phthalates thanks to a widely reported-on 2005 study by Shanna Swan:
“Swan claimed that levels of certain phthalate metabolites in pregnant women correlated with a lower anogenital index in their male children (the AGI is a measurement of the distance from the anus to the base of the penis, divided by the weight at the time of measurement)
There wasn’t a consensus as to what a normal range for AGI was in baby boys or whether it is significant, but there was evidence that a shorter AGI correlated with a slower rate of testicular descent in animals. When a National Institutes of Health expert panel later evaluated her study, it didn’t find her evidence wholly convincing. All the babies in the study had normal genitalia with no sign of defects.
In short, there were no grounds for panic. But Swan wrote an op-ed for the San Francisco Chronicle claiming that “In-utero exposures to phthalates can lead to birth defects and genital malformations … in baby boys.” It didn’t matter that her study never even considered this hypothesis, or that such a claim wouldn’t have passed peer review based on the data she provided: Environmental activists and journalists seized on her public comments as proof the public was at risk. Phthalates and Shanna Swan suddenly became the poster boy and girl for deformed penises.”
This most recent study involved Swan going back to the mothers of the boys in her 2005 study and asking questions about the way they play, a method Butterworth (and UrbanBaby) finds suspect. Phthalates may indeed turn out to have feminizing effects on humans (much research has already been published on their effects on frogs), but Butterworth points out that better research than Swan’s needs to be done to pinpoint just what’s going on. Until then, no need to panic. Or push trucks on your boys.
You know what annoys me? When manufacturers stick my kid into a gender box. Walk into any kids’ clothing or furniture store and you’ll see that the store is divided right down the middle between products meant for boys (blue, green, trucks, dinosaurs) and for girls (pink, purple, fairies, butterflies). The message is clear. Boys can be powerful and productive, girls should stick to being decorative.
