Abstract
This disputatio is an inquiry into the nature of the truly human sexual act. The authors first present and critique the types of complementarity - heterogenital, reproductive, communion, affective, and parental - that the magisterinm finds in a truly human sexual act. They then suggest that heterosexual or homosexual orientation as part of a person's sexual constitution requires adding orientation complementarity to the equation. This addition yields the conclusion that holistic complementarity - an integration of orientation, personal, and biological complementarities - is a more adequate sine qua non of truly human sexual acts.