" The reproductive revolution has shaken up all the relationships once taken for granted between sex, marriage, conception, childbirth, and parenting. People who could not become parents before can now do so in such bewildering combinations that a child can potentially have five different parents: a sperm donor, an egg donor, a birth mother, and the social father and mother who raise the child. On the other hand, some married couples use new reproductive technologies to avoid having children altogether. Seen in this light, a childless marriage is just as much a challenge to the tradition that children are the central purpose and glue of a wedded relationship as is a gay union. "

― Stephanie Coontz , Marriage, a History: From Obedience to Intimacy or How Love Conquered Marriage