Day 304: Male and Female

Each of the two sexes is an image of the power and tenderness of God, with equal dignity, though in a different way. The union of man and woman in marriage is a way of imitating in the flesh the Creator's generosity and fecundity: "Therefore a man leaves his father and his mother and cleaves to his wife, and they become one flesh" [Gen 2:24]. All human generations proceed from this union. CCC 2335

In today's reading, the Catechism begins with the Sixth Commandment by discussing men and women. The union of the two sexes in marriage is necessary for procreation and the continuation of our species. Sure, babies can be made outside of the marital bond, but as we've seen, this does not go well for them or society as a whole. So "the harmony of the couple and society" depends upon the differences, support, and "complementarity" they bring to the marital union (CCC 2333). 

The Catechism Compendium summarizes the responsibility we have regarding our own sexual identity:

God has created human beings as male and female, equal in personal dignity, and has called them to a vocation of love and of communion. Everyone should accept his or her identity as male or female, recognizing its importance for the whole of the person, its specificity, and complementarity. (#487)

The Catechism Companion Vol III has some good commentary on this:

God could have made us like the angels, but when he made human beings, he made them male and female... The first command that God gave to the human race was to procreate, that the love in coming together as male and female would create more life. As you walk through life as a woman or as you walk through life as a man, your life is touched in every way by your womanhood or manhood. Your body matters. The human being is a body-soul composite. (p 124)

This is why transgenderism, so popular among some in modern culture, is something that cannot be accepted or promoted. Besides the fact that it is impossible to change one's biological sex, gender comes from the body we are born with, and "gender cannot be separated from the whole person". Whether we are male or female, we are all born with the gender that God intended to give us.