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FEATURED STUDY: The Link Between Phthalates Exposure and Children Play Behavior

Higher levels of exposure to phthalates in early pregnancy stages are associated with less masculine types of play.

Higher levels of exposure to phthalates in early pregnancy stages are associated with less masculine types of play

Research by

Sarah Evans, PhD, MPH. Assistant Professor at theDepartment of Environmental Medicine and Public Health.


Phthalates are chemicals that are added to some plastics as well as fragrance so are present in every day consumer products such as toys, food packaging, vinyl flooring, cosmetics, and cleaning products. For this reason, nearly everyone has phthalates in their bodies. Past studies have shown that phthalates interfere with hormones in our body and lead to impaired development of the reproductive system and increased risk of problem behaviors in children.

Because hormones also shape some of the differences we see in boys’ and girls’ brains and behavior, we asked whether phthalate exposure during pregnancy was associated with changes in typical play behavior among boys and girls at age 4-5 years.


We found that when moms had higher levels of exposure to some phthalates early in their pregnancy, they reported that their sons were less likely to engage in types of play that are typically viewed as more masculine, such as playing with cars, climbing, and playing sports and ball games. This makes sense given what we know about phthalates and about how the brain develops. Phthalates have been shown to interfere with testosterone, the male sex hormone that helps to pattern the brain during early prenatal development. The connection between phthalates and play behavior persisted even when we accounted for parental attitudes about opposite gender play, whether the child had an older same sex sibling, maternal education, child age, and race.

What does it mean?

It is important to understand that even low levels of environmental chemicals like phthalates can interfere with brain development and behavior. We did see a reduction in phthalate levels in study participants compared to earlier studies, which is likely due to the phasing out of some phthalates from certain products and availability of safer options. This is great news because it means that consumer awareness and policy changes can reduce risk of exposure to phthalates. However we found that Black participants and those with lower education and income levels had higher levels of phthalates in their bodies, suggesting a need for more targeted efforts to protect these populations from harmful exposures. We need tighter regulations to keep phthalates out of products and increased access to phthalate-free and other safer products for all people regardless of background and income.

In the meantime, we can reduce exposure to phthalates by avoiding plastics made with PVC or vinyl, or labeled with the # 3 recycling symbol, and choosing fragrance-free and phthalate-free soaps, cosmetics, and cleaning products. Phthalates leave the body within a day or so of exposure, so making simple changes can have a rapid effect on reducing exposure.