Catechism of the Catholic Church §383 — excerpt
"God did not create man a solitary being. From the beginning, "male and female he created them" (Gen 1:27). This partnership of man and woman constitutes the first form of communion between persons" (GS 12 # 4).
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.