In this segment of the video, Josh and Carrie discuss the way that marriage is not like being roommates who live together, but separately. Man and woman are made for each other in a way that is absolutely unique. We see this through their sexual difference, even if we just look to the human body as male or female. A man’s body does not make sense by itself, nor does a woman’s; only together is it possible to get the whole picture of humanity. At a deeper level, as Josh says in the video, there is also a longing of the one for the other. There are always and only two ways of being human: we cannot be the other, so we want to be with the other.
We are made for union and communion, to be in relation with others.[i] In Genesis, God says, “It is not good for the man to be alone” (Gn 2:18). God’s solution to man’s isolation is not to create another identical man. Rather, He creates a woman from the man’s side and gives the two to each other in the first marriage. “For this reason, a man shall leave his father and mother and be joined to his wife, and the two shall become one flesh” (Mt 19:5; cf. Gn 2:24).
The two become one flesh in the physical act of sexual intercourse, in which the bodies of the man and woman cooperate in an act which may bring about the procreation of another human being. As Eve says, “I have produced a male child with the help of the LORD”(Gn 4:1). There is only one “combination” of human bodies that can produce new life: a man and a woman. If you accept the idea that human life has special value, then you should also accept that the (one and only) natural action that can bring this life into existence is, by that fact, unique in its power and importance to the world.
The truth of the human person, created male and female, and the truth of what marriage is, are not only concerns of religion or religious people—they are truths that affect everyone.
- Why is it important to society that marriage be based on sexual difference?
- Why is the fact of our being created male and female not simply a tool for the survival of the species?
 Even in those rare cases of atypical genetic or physical development, the fundamental question is whether the person is male or female. There are only “X” and “Y” chromosomes, there is no “other” sex. In such cases, we rely on natural science that can help determine biological sex. This knowledge will help the person to understand his or her sexual identity.
[i] See CCC, nos. 45, 371-372, 1603-1604, and 1877-1879.