(CNN) -- For the first time, same-sex marriage has been approved by a popular vote in the United States.
Voters in Maryland and Maine passed referendums by narrow margins cementing the right for people to marry, regardless of gender.
The words man and woman "relating to the marital relationship or familial relationships must be construed to be gender-neutral for all purposes," Maine's act says. "Civil marriage laws allow gay and lesbian couples to obtain a civil marriage license," reads Maryland's.
Results of a vote on the same issue was still pending in Washington, as was a measure that would ban same-sex marriage in Minnesota.
"History was made tonight," said Paul Guequierre, spokesman for Human Rights Campaign, which fought for the ballot box victories for same-sex couples.
Election Day brought two additional gains for proponents of same-sex marriage, said the Gay & Lesbian Alliance Against Defamation.
"Tammy Baldwin of Wisconsin became the first out gay U.S. senator," GLAAD spokesman Rich Ferraro said. "President Obama becomes the first acting president to support marriage equality and win re-election."
The two ballots that passed, called "Question 1" in Maine and "Question 6" in Maryland, contain similar language and also explicitly mention the right of clergy to refuse to wed gay and lesbian couples, if it goes against their religious convictions.
"This chapter does not require any member of the clergy to perform or any church, religious denomination or other religious institution to host any marriage in violation of the religious beliefs of that member of the clergy, church, religious denomination or other religious institution," Maine's Question 1 states.
The governments of both states had passed laws permitting same-sex marriage, but activists opposed to the laws collected enough signatures to put them to a ballot, said Fred Sainz spokesman for HRC, which raised $32 million for its campaigns on the referendums that included radio and television ads, social media strategy and on-the-ground canvassing by thousands of volunteers.
Sainz believes the effort paid off. A similar referendum in Maine failed in 2009, when voters rejected their governor's decision to allow same-sex marriage. Tuesday's results represent a turnaround.
Thirty-eight states have passed bans on marriages between people of the same gender, mostly by amending their constitutions to define marriage as the union between a man and a woman.
In the six states -- Massachusetts, Connecticut, Iowa, Vermont, New Hampshire and New York -- and the District of Columbia where gays and lesbians have previously won marriage rights, it was because of actions taken by judges or legislators, not voters.
National polls have recently shown a shift in attitudes towards same-sex marriage, with a majority of Americans now approving of marriages between two men or two women.