Dual Uncertainties: On Equipoise, Sex Differences and Chirality in Clinical Research

Ethical justification for clinical research may invoke equipoise, an element of scientific uncertainty regarding the superior choice if presented with different therapeutic options. Given a relative lack of scientific knowledge available for females related to historic tendencies for research to focus predominantly on males, clinical equipoise alone when applied to the context of sex differences may not be sufficient for us to appreciate whether or how a therapy might vary in its effects depending upon participant sex. I explore the analogy of chirality or 'handedness,' arguing we might think of the two sexes as possessing this property: female and male are equally human, yet knowledge of the biology of one sex cannot be completely superimposed onto the other. I propose the concept of chiral equipoise, suggesting that in ethical deliberations around clinical research we consider not only the uncertainty between therapeutic options, but also ask: for which sex?