Catholic sexual ethics speaks extensively about bodies, yet rarely asks whose embodied experience is permitted to shape its moral authority. This paper examines the methodological tensions within Catholic sexual ethics through a critical reading of Humanae Vitae and its contemporary defence in Janet E. Smith's natural-law interpretation, placing them in dialogue with the feminist liberation theology of Ivone Gebara. While Humanae Vitae presents its teaching on contraception as an expression of objective moral truth grounded in the nature of the human person and the conjugal act, its ethical reasoning relies on a biologically centred account of normativity in which the unitive and procreative meanings of sexual intercourse are treated as inseparable and universally binding. Janet Smith, despite explicitly rejecting reductive "physicalism," largely preserves this framework by translating biological teleology into the personalist language of self-gift, self-mastery, and the "language of the body." This paper argues that such approaches reveal a deeper epistemological limitation: women's embodied experiences of fertility, reproductive labour, vulnerability, trauma, and socio-economic constraint rarely function as sources of moral knowledge within the ethical framework itself. Instead, these realities appear primarily as circumstances to be disciplined by pre-established norms. Drawing on Ivone Gebara's feminist theology, the paper proposes that women's everyday experiences of suffering, survival, and relational interdependence constitute genuine loci of moral discernment rather than merely pastoral concerns. Rather than offering a doctrinal adjudication of Catholic teaching on contraception, the paper interrogates the method by which moral authority is constructed. It argues that a sexual ethic claiming universality risks losing credibility when women's bodies are structurally prevented from shaping its moral reasoning.