SEX ASSIGNED AT BIRTH

Transgender rights discussions often turn on the distinction between "gender identity " and "sex assigned at birth. " Gender identity is a person's own internal sense of whether they are a man, a woman, or nonbinary. "Sex assigned at birth " means the male or female designation that doctors ascribe to infants based on genitalia and is marked on their birth records. Sex assigned at birth is intended to displace the concept of "biological sex. " This Article provides an account of the origins of the terms "biological sex " and "sex assigned at birth " and assesses the potential of the shift to sex assigned at birth for transgender rights arguments. The debate is not one over mere nomenclature. This Article's examination reveals that the term "biological sex " rose to prominence to lend a veneer of scientific support to projects denying the validity of transgender identities and that the unquestioned use of that concept continues to underwrite exclusion. By referring instead to sex assigned at birth, transgender rights advocates convey that "biological sex " is not simple, static, or binary and that gender identity also has biological aspects. Furthermore, the phrase "assigned at birth " invokes philosophical arguments against assigning particular social roles to individuals at birth. It taps into the moral intuition that a person's genitalia and health data are private matters. This Article argues that sex assigned at birth is an important concept that clarifies the stakes of disputes over transgender rights. But it cautions that this conceptual shift is not sufficient to secure victories in transgender rights litigation. Ultimately, definitional debates about sex and gender cannot resolve the moral and practical questions at the heart of contemporary controversies over transgender rights. Recent legal vic-tories on transgender rights issues have done more than debate the meanings of sex and gender: They have addressed practical objections to transgender inclusion, cultivated empathy for plaintiffs, and staked claims in the registers of equality, autonomy, and dignity.