As lawyers debated gay marriage inside the Supreme Court on Wednesday, activists outside delivered speeches, cranked up boom boxes and hoisted hand-made signs. “Kids do best with a mom and dad,” one said; “Jesus had two dads, he turned out OK,” another declared.

Advocates for same-sex marriage turned out in larger numbers than supporters of the Defense of Marriage Act, which denies federal benefits to legally married gay couples and was before the court. But the crowd of hundreds was smaller than the raucous gathering for Tuesday’s arguments on California’s ban on same-sex marriage.

J. Mary Sorrell, a justice of the peace in Northampton, Mass., said she has married more than 500 gay couples and many struggle with federal tax law, the denial of spousal Social Security benefits and the “little insults,” such as not being able to check the box for “married” on federal forms.

“To eliminate that would be huge,” she said.

The law’s constitutionality was the issue, but many of the law’s defenders drew their arguments from biblical verses, including a man in sackcloth carrying a Bible, a ram’s horn and a placard that cited Mark 10:6-7: “God made them male and female, and said a man shall be joined to his wife.”

James Manship came dressed as George Washington, in a navy and tan Continental Army uniform with seven stars on his epaulets. “If we destroy the institution for the production of children,” he said, “we ruin the system for the republic to be perpetuated into the future.”

Monika Vinje, an international relations student at George Washington University, stayed up late with friends to make signs.

“I’m excited to see the progress,” she said, gesturing to the hundreds of gay-marriage supporters waving rainbow flags and American flags.

Proponents erupted in cheers when Edith Windsor, the lesbian widow whose lawsuit was taken up by the court, walked down the steps after the session. “I think it went beautifully,” she said, describing the justices as “gentle” and saying they “asked all the right questions.”

Windsor, 83, argued that the federal government discriminated against her when she was required to pay a higher estate tax bill than a married couple after the death of her wife in 2009.

Roberta Kaplan, the lawyer who argued the case, said, “I think everyone now agrees that Edie Windsor gets her money back from the federal government.”

Defenders of the Defense of Marriage Act expressed disappointment.

“I have to be realistic,” said the Rev. Robert L. Schenck, chairman of the Evangelical Church Alliance, which filed a brief in the case and represents clergy members. “A strong case was made against DOMA.”

Schenck said he is concerned that clergy, including military chaplains, could be required to recognize same-sex unions if the law is struck down, which he said would violate their religious freedom.

“Separate but equal never worked,” said Blair Dottin-Haley, a gay African-American man who was married in Washington, D.C. Dottin-Haley and his partner live in Virginia, which bans same-sex marriage. He compared his situation to that of his grandparents, who fought for equal rights in the 1960s.

“This is this generation’s Brown v. Board of Education that is being heard today,” he said, referring to the landmark 1954 school desegregation case.