Many people have expressed surprise at the speed with which same-sex unions went from being a crime and a sin to being a constitutional right.

Exactly 50 years ago, to far less fanfare, the Supreme Court of the United States decided that married couples had a constitutional right to prescription contraceptives. (The FDA had approved the pill just five years earlier.) In 1971, the Supreme Court ruled that single people had the same right.

The Economist called the pill the most important scientific advance of the 20th century. It certainly has changed the way we live. It also paved the road for the Supreme Court's decision in Obergefell v. Hodges, the same-sex marriage case.

Before the pill was readily available, sex and children and lifelong commitment were all part of one contract. Sex naturally led to children, or at least held forth that possibility. People understood (and still do) that children need to grow up in stable and permanent families.

So closely were these three things (sex, children, marriage) tied together that sex was referred to as the "marital act." This was our social practice, enforced by notions of virtue, counsels of prudence, legal rules and social taboos.

The pill allowed us to split what once was one contract into three. Today, there is no necessary connection between sex and children. And if there are no children in prospect, sex needn't lead to marriage. It might be just a pleasing form of recreation. Even within marriage, children are now a matter for negotiation.

All this has had predictable effects. The idea that there is a virtue (chastity) connected with how and when we have sex seems almost quaint. Instead, we have radio and TV personalities like Dr. Ruth Westheimer encouraging us to have "good sex," part of the name of her show.

Young people are certainly taking her advice, but they are no longer getting married. The Pew Research Center recently reported that 69 percent of young adults (age 18 to 24) believe "society is just as well off if people have priorities other than marriage and children."

For almost half of women age 15-44, cohabitating was their first union, not marriage, according to a report by the National Center for Health Statistics. The same report showed that informal relationships don't usually last -- the median duration of a first cohabitation is 22 months.

Elizabeth Anscombe, a British analytic philosopher, presciently observed, back in 1972, that "if sexual union can be deliberately and totally divorced from fertility, then we may wonder why sexual union has got to be married union."

Indeed, she said, if we disconnect sex from children "there is no reason why ... 'marriage' should have to be between people of opposite sexes." She was right on both counts. The fracturing of our sexual contracts brought about by the pill has led us to reframe same-sex marriage as an issue of equality and discrimination, not of children and societal health.

Is there any chance of getting our culture to embrace, once again, the Catholic view about sexual relations between men, or between women? I don't think so, unless we see an equally revolutionary change in the behavior of heterosexual couples. Unless they themselves recover the virtue of chastity -- unless they view sex as necessarily connected to marriage and fertility -- they have no moral warrant for imposing it on their gay friends.

JOHN GARVEY IS THE PRESIDENT OF THE CATHOLIC UNIVERSITY OF AMERICA IN WASHINGTON.



- Garvey is president of The Catholic University of America in Washington, D.C.