– UPDATED: Should Gay Marriage Be Legal? – Gay marriage is legal in 35 US states and the District of Columbia, and is banned in 15 states. Proponents contend that gay marriage bans are discriminatory and unconstitutional, and that same-sex couples should have access to all the benefits enjoyed by different-sex couples. Opponents contend that marriage has traditionally been defined as being between one man and one woman, and that marriage is primarily for procreation. Explore our updated pro and con arguments, plus “Did You Know?” facts and background information on the history of the gay marriage debate.