Hidden Guests” explores how the emerging field of microchimerism is upending medicine, genetics, and our sense of self.

Longstanding regulatory and testing gaps have historically been filled by third-party groups with questionable methods.

Drugmakers claim that broad state PFAS laws are overly burdensome. But environmental health experts aren’t convinced.

A massive Swedish study examined hormonal birth control risks. But the nuances of such studies get lost on social media.