Is sex evil unless it leads directly to babies? Is marriage only legitimate if it fosters offspring, or is it also for intimacy? The U.S. Supreme Court issued three decisions between June 7, 1965 and Jan. 22, 1973 that collectively give the answer: No. Roe, the last of them, can be thought of as the exclamation mark. As we reflect on the 40th anniversary of that decision, there's another group that has Roe to thank for the rights it enjoys today: LGBT Americans. While many of us in the LGBT community see parallels between the gay and women's rights movements, we often overlook the direct role of Roe in establishing a right to same-sex marriage: If women are permitted to have sex without offspring—even if their contraception fails and those little cells start dividing inside them—then it must also be okay for women and women, or men and men, to have sex without the possibility of fertility. Reproductive freedom and LGBT freedom are two sides of the same idea.