Baby-bottle plastic causes aggression?

Posted on December 23, 2011


Image: University of Cincinnati, via

Dateline: 24 October 2011 // Posted by: Raquel Avila
Source: Daily Mail,

Story: “Gender-bending chemical that ‘makes girls as young as three, aggressive and hyperactive”

Summary: A newly published paper in the journal Pediatrics links Bisphenol A with problematic behaviour in 3-year-old girls.

Bisphenol A is a common chemical  used in many products such as baby bottles, polycarbonate plastics, toys, water pipes, drinking containers, sports safety equipment, dental monomers, medical equipment etc. It is one of the highest volume chemicals produced worldwide, with over six billion pounds produced each year.

The Daily Mail claims that “scientists have found that that those (girls) exposed to high levels of BPA in the womb are more likely to suffer from behavioural problems … Scientists think that … relatively low doses can interfere with our behaviour, bodily functions and fertility.”

All these claims come from the study published in Pediatrics. Its methodology is not included in the articles that were published in the news. In the article doctors are advised to tell worried women to reduce their exposure to this chemical during pregnancy, furthermore, EU is recommended to take action to protect future generations from health risks.

Why is this PseudoNews? The link between BPA and behaviour disruptions is one that should be considered carefully. In this case, the article contains many instances of affirming a causal relationships using a pretty straightforward acclamation, such as “makes girls as young as three, aggressive and hyperactive”. Furthermore the article also claims that relatively low doses can cause this effect. There is no reference in the article as to how much a low dose is, nor the amount found in the products containing the chemical in question. Moreover, the research assesses the kids’ behaviour with a questionnaire to the parents; the behaviour hasn’t been observed directly by any of the researchers. All the data is based on the parents’ perspective, which is likely to be very subjective.

What features of pseudoscience are on show? First of all, the lack of parsimony in the article is a problem. Can the children’s behaviour be explained by other means? Maybe the behavioural differences between genders are caused by the perception of the parents. It is normally more accepted that boys are more active and aggressive than girls and it is possible parents have not reported boys behaviour correctly.

Furthermore, this article is an example of false cause. It links the behavioural disruption and the chemical as forming a cause–effect relationship, when in fact the real research article does not.

It also creates a straw man, misrepresenting the research paper claims. In fact, if we bother to find it and read it, we find it makes very different claims; for example: “ This pattern should be interpreted cautiously, given the imprecision of the observed associations among girls and the low statistical power for interactions between gender and BPA exposures”, “ gestational BPA exposure might be associated with anxious, depressive… behaviour” and “benefit of reduction of exposure to certain products is unclear”.

The news in the Daily Mail is appealing to fear, using the threat of harm from the chemical to advance their position, and suggesting banning something that is not even demonstrated to be toxic form the human being.

The moral of the story: News allegations should be looked at very carefully, and if anything seems out of place, a second look at the real source would be worth the time.