The barriers to women's participation as subjects in biomedical research are currently being challenged as a matter of legislative policy, medicine, and law. This Article catalogs the ways in which women have been disadvantaged by their exclusion and recent developments to redress them, and goes on to dissect the underlying rationales for excluding women from clincial trials. The author reveals the ‘fundamental misconception’ behind exclusionary rationales, and argues that research sponsors in fact have more to fear in the way of potential liability from the exclusion of women, even pregnant women and women of child-bearing capacity, than from their inclusion. Finally, the Article suggests strategies for achieving reform of these exclusionary practices.