We might forget. Bruce Jenner is a man.
From the Catechism of the Catholic Church:
355 “God created man in his own image, in the image of God he created him, male and female he created them.”218 Man occupies a unique place in creation: (I) he is “in the image of God”; (II) in his own nature he unites the spiritual and material worlds; (III) he is created “male and female”; (IV) God established him in his friendship.
371 God created man and woman together and willed each for the other. The Word of God gives us to understand this through various features of the sacred text. “It is not good that the man should be alone. I will make him a helper fit for him.”242 None of the animals can be man’s partner.243 The woman God “fashions” from the man’s rib and brings to him elicits on the man’s part a cry of wonder, an exclamation of love and communion: “This at last is bone of my bones and flesh of my flesh.”244 Man discovers woman as another “I”, sharing the same humanity.
372 Man and woman were made “for each other” – not that God left them half-made and incomplete: he created them to be a communion of persons, in which each can be “helpmate” to the other, for they are equal as persons (“bone of my bones. . .”) and complementary as masculine and feminine. In marriage God unites them in such a way that, by forming “one flesh”,245 they can transmit human life: “Be fruitful and multiply, and fill the earth.”246 By transmitting human life to their descendants, man and woman as spouses and parents cooperate in a unique way in the Creator’s work.247