This essay aims to clarify the debate over same-sex unions by comparing it to the fourth-century conflict concerning the nature of Jesus Christ. Although some suppose that the council of Nicaea reiterated what Christians had always believed, the Nicene theology championed by Athanasius was a dramatic innovation that only won out through protracted struggle. Similarly, despite the widespread assumption that Christian tradition univocally condemns homosexuality, the concept of sexuality is a nineteenth-century invention with no exact analogue in the ancient world. (...) Neither heterosexuality nor homosexuality is addressed directly in Christian tradition; for this reason, the significance of older authorities for the modern debate is necessarily indirect. The dichotomy between progressive and conservative positions is therefore misguided: it is necessary neither to abandon tradition for the sake of progress nor to oppose innovation for the sake of fidelity. (shrink)