Abstract

The recent case of German siblings Patrick Stübing (age 30 years) and his sister Susan Karolewski (age 22 years) has reignited debate over the criminalisation of sexual intercourse among consanguine descendants. The primary justification for criminalising incest is the purported increased risk of genetic disabilities among offspring, but is criminalising sexual intercourse an empirically sound and proportionate response to this increased risk? To answer this question we must consider the specifics of the harm in question (eg, is it a harm to the child or a societal harm) and the magnitude of the harms of the intervention. The example of incest law has important implications for liberal societies. If we can justify imprisoning consenting adults for choosing partners who will increase the risk of having children with disabilities, then we set a troubling precedent for all couples who may pass on genetic disorders to their children.