Sometimes it takes considerable statistical expertise to diagnose the errors journalists make in health reporting; sometimes it just means reading the study they claim to be reporting on and particularly the conclusion, where the authors talk about the "limitations" of their findings; and sometimes it just requires a basic knowledge of biology. In the case of the August issue of Vogue, make that very basic knowledge indeed.
In an article, which rides the never-ending "common chemicals-may-be-causing-infertility" bandwagon, Vogue warns readers about phthalates, a class of chemicals which make plastic flexible.
"When the fetus is exposed to phthalates ... they may cause malformation of the reproductive tract in males and decreased semen quality....phthalate exposure during adulthood may lead to menstrual irregularities and to miscarriage."
Um, boys don't produce semen until they reach puberty - and even the most precocious male is not going to reach puberty before leaving the womb. Nor have any actual baby boys suffered malformed reproductive tracts as a result of phthalate exposure. Vogue writer Robert Sullivan reports that
"Most recently, [Shanna Swan] and a team of scientists published a paper hat showed the prenatal exposure to phthalates - one type of endocrine disruptor found in plastic bottles and toys, among other things - adversely affects genital development in boys."
But if you read the study, Swan did not find any adverse genital development - all the baby boys in her study were normal. What she found were a number of correlations between phthalate metabolites in the urine of pregnant women and a biomarker in their children which she believes supports the *hypothesis* that phthalate exposure adversely affects genital development in males. But as Swan admitted, the "reliability" of the biomarker in humans "has not been established."
An expert panel under the auspices of the National Toxicology Program agreed on that point, and found Swan's research inconclusive and her data "insufficient" to warrant the other, more alarming conclusions that she made (which became ever more alarming the closer the proximity to a reporter). The panel recommended she do her study again with a larger sample of children. (It's still an important question that needs to be settled).
As for the idea that there are phthalates in plastic bottles, well, there aren't any: the confusion stems from similar-sounding chemical component names that are quite chemically different.
And while we're at it, it's worth pointing out that the risk of menstrual problems and miscarriage is to *animals* and not to *humans* -- and specifically laboratory animals who have been dosed with massive amounts of phthalates to the point of toxicity. Workers in PVC plants with high occupational exposure to phthalates have not shown evidence of either problem.
So, if you're pregnant, chug away on that water bottle without fear (and don't smoke, take vitamins, eat a proper diet, etc). If you want to be really safe from phthalates, just avoid eating your garden hose with several chasers of nail polish.