How should Christians in science engage in the gender debate? Much of that debate is about matters of empirical fact: the causes and consequences of what is called “gender incongruence,” and the benefits and harms of various interventions. On the other hand, some thinkers and activists who accept the reality of such facts also deny their relevance, and insist that what matters is simply how a person feels and what a person wants. Neither the “appeal to facts” nor the “appeal to feelings” are legitimate grounds for debating the question of whether gender incongruence is, in some sense, a medical problem to be fixed, or whether it is an identity to be celebrated. Only by making “ethical judgments”—fallible claims about objective values—can we address that question coherently and faithfully.