03/25/2008 12:16 pm ET Updated Nov 17, 2011

The Case Against Worrying About Phthalates in Children's Toys

Mark Shapiro, an investigative journalist, makes the case on the Huffington Post about the need to ban phthalates in children's toys. Responding to the charge that he had abandoned journalism for activism, he argues: "My work was reporting the findings of scientists about the apparent havoc wreaked on infant's developing metabolism from phthalates."

But there's a problem: if you are going to muckrake with science, you need to be able to refute scientific evidence which doesn't agree with your hypothesis. That's how science works. Posit a theory, find evidence (or find data and posit a theory), test that evidence and theory against everything else out there.

This, Shapiro doesn't do. He takes only the evidence that supports his position and avoids addressing the problems with it, even though these problems are substantial.

For instance, Shapiro cites "abundant peer-reviewed" evidence for the risks from phthalates, yet he ignores when one of the key pieces of that evidence was called into question by an expert panel of the National Toxicology Program, as Dr. Shanna Swan's key study on phthalate exposure was.

According to Shapiro, Dr. Shanna Swan, Director of the Center for Reproductive Epidemiology at the Rochester University School of Medicine and Dentistry, found "a corollary between the phthalate intake of pregnant women and decreased ano-genital distance in their male offspring."

Actually, she didn't. She claimed to find a correlation. Corollary and correlation don't mean the same thing. More to the point, the anogenital distance was rejected as a biomarker by the expert panel as no-one has determined what a normal range for AGD is to begin with.

And while there is a norm for the anoscrotal distance, Swan's study found no correlation between that marker and in utero phthalate exposure. Swan's statistical correlations were also re-evaluated and found weaker than she claimed.

But most interesting of all, Swan didn't find a statistically significant correlation between the phthalate Shaipiro cites as being widely used in toys - DEHP - and AGD.

It might also have been useful to tell readers that all the baby boys in Swan's study had normal genitals and reproductive functioning. What her statistics showed was a trend whereby a shortened anogenital index might indicate that phthalate exposure in utero is associated with reduced penile volume and delayed testicular descent. One key problem is that she didn't control for premature birth in her study, and as premature babies are much more likely to have undescended testicles, so this may have skewed the results.

Now Swan has repeatedly talked all of this up as indicating the possibility of the "feminization" of boys, which Shapiro notes. But that stretches her evidence beyond breaking point - and I sincerely doubt that many toxicologists or endocrinologists would subscribe to that interpretation of the statistics in her study. In fact, most toxicologists I've spoken to about Swan's work (none of them industry-affiliated) have said, her research is interesting, but that there needs to be a lot more study.

Shapiro however, doesn't seem to believe that this sort of measured interest is sufficient given that the European Union have banned phthalates in children's toys.

But in an astonishing omission for an investigative journalist, Shapiro neglects to mention that the ban was political and not scientific in origin. Indeed, the head of the European Commission's own Scientific Committee on Toxicity, Ecotoxicity and the Environment, which found no risk to children from phthalates in toys, described the European Commission Directorate for Public Health and Consumer Safety decision to push for a ban as a "gross misuse" of its research.

Bringing up the ban without explaining that it was instituted over the objections of the European Commission's own scientists might be said to be a rather gross journalistic license. But it also underscores what the public loses by an investigative journalist getting out of his scientific depth with a topic.

Let's for the sake of argument, say that DEHP, the phthalate Shapiro cites as prevalent in toys, is a reproductive risk to children: if you look at in utero and postnatal exposure routes, the overwhelming source for DEHP is not toys! It's food and dust (from paint), which the latest EU risk assessment points out. In other words, given the disparity, banning toys will have no discernible impact on public health.

That's why it's important to look at ALL the evidence, and not just the stuff that makes for a good muckraking scare story that gets PBS and NPR viewers all hot and bothered about evil corporations. For if Shapiro and Swan et al are right, we're devoting a huge amount of energy to a false solution to the problem. If, that is, they are right. At present, the scientific arguments driving their claims are a lot weaker than they'll admit. But good journalism, like good scientific research, faces up to what it doesn't know, or can't answer, and deals with the strongest evidence against its claims honestly.