When Mark Takano ran unsuccessfully for Congress twice in the early 1990s, his opponents tried to smear him as a “homosexual liberal” and a “nutzoid.” One of them even had pink fliers printed that asked, “A Congressman for Riverside ... Or San Francisco?”

When he ran again last year, he won by almost 20 points. “Flash forward 18 years,” Mr. Takano said recently, “and the very macho building tradesmen are behind me. I’m getting pictures with them in their hard hats.”

...in the 113th Congress there are six openly gay or bisexual members in the House — a small but tangible sign that their presence at the highest levels of government is no longer something only whispered about. The Senate has its first lesbian, Tammy Baldwin of Wisconsin. The lawmakers’ partners, no longer relegated to the shadows or introduced generically as “friends,” stood beside them on the House floor when they were sworn in this month. Their adopted children are attending Congressional retreats.

And this week they sat in President Obama’s presence as he insisted on equality for “our gay brothers and sisters,” words few of them ever expected to hear in a president’s Inaugural Address.

Congress has never been an accurate reflection of the country it serves. It remains far whiter, wealthier and more male than the nation’s population. But as their numbers in Congress gradually increase, there is a sense among these newcomers that they are forcing some of their colleagues to rethink gay rights and homosexuality. The presence of openly gay men and women and their families was a factor that many believe was decisive in turning the tide for states where same-sex marriage was legalized by legislatures. Seeing them helped put a human face on a concept that many legislators had thought about only in the abstract...

...“It’s becoming — ever so slowly — more than a novelty to be a gay member of Congress,” said Representative David Cicilline of Rhode Island. Like all the openly gay, lesbian and bisexual members, Mr. Cicilline is a Democrat.

Representative Jared Polis of Colorado observed that it was not too long ago “when it was just Barney and Tammy.” He was referring to Ms. Baldwin, a member of the House before she was elected to the Senate, and Barney Frank of Massachusetts, who retired but was the first member of Congress to speak openly about his homosexuality.

“But with six of us” in the House, “it’s harder to keep track. And it’s always going to be assumed that there are gays and lesbians in the room,” added Mr. Polis, who has a young son with his partner and is the most senior gay member of the House. Together the six of them will lead a caucus that will champion gay rights and other equal protection issues. The other members will include Mr. Cicilline; Mr. Takano of California; Sean Patrick Maloney of New York; Kyrsten Sinema of Arizona, who is bisexual; and Mark Pocan of Wisconsin.