Exposure to flame retardant chemicals is relatively ubiquitous among the general public, and research has demonstrated that these contaminants can pass from a mom to her baby through the placenta. Recently we conducted a study that measured brominated flame retardant levels in human placental tissues from a group of women in North Carolina. Our research group measured a suite of polybrominated diphenhyl ether (PBDEs), 2,4,6-tribromophenol and thyroid hormone levesl (T4, T3 and rT3) in each tissue sample. Significant associations were observed between the flame retardants, and thyroid hormone levels in the placenta. Further, we found that concentrations were significantly higher in the placental tissues if the placenta was associated with a male infant, compared to a female infant (see Leonetti et al. 2016). The factors or variables driving this difference in flame retardant accumulation are unclear, but we are conducting further research to determine if this may be related to differences in metabolism, or differences in active uptake of the flame retardants. We are also exploring the effects of flame retardants on thyroid and estrogen signaling and production in the human placenta. This research has been supported by a grant from the National Institute of Environmental Health Sciences (R01ES020430).