If you have been paying attention to the news reports on buying safe toys this holiday season, you’ve probably heard about phthalates.

Pronounced tha-lates (or sometimes thay-lates), this group of chemicals has been shown to disrupt hormones in laboratory animals. Fetal exposure to phthalates has also been linked to reproductive diseases later in life in baby girls. Fetal exposure has also been associated with decreased ano-genital distance in baby boys, leading the lead researcher to charge phthalates with causing the “feminization” of baby boys (this research has been challenged by other scientists).

A recent study found occupational exposure to hairspray by pregnant hairdressers and others doubled their risk of having baby boys born with the genital defect hypospadias (where the opening for the urinary tract is not located at the tip of the penis).