French right-wing members of Parliament leave while French Justice Minister Christiane Taubira (right) is delivering a speech on Feb. 12, 2013 at the French National Assembly in Paris. The assembly voted today by a clear majority to adopt legislation allowing gay couples to marry and adopt children. (JACQUES DEMARTHON/AFP/GETTY IMAGES)

After months of philosophical debate and massive street demonstrations for and against, the French National Assembly on Tuesday authorized same-sex marriage and adoption by gay couples, despite France’s long history as a homeland for Roman Catholic tradition.

The legislation, passed 329 to 229 with 10 abstentions, was France’s most far-reaching social change since abolition of the death penalty in 1981. The measure is scheduled to be taken up in April by the Senate, where the ruling Socialist-led coalition enjoys a majority and is likely to confirm the lower-house vote, making same-sex marriage the law of the land despite warnings that it undermines the foundations of French society.

“This is a vote of pride,” said Thierry Mandon, speaking for the Socialist Party parliamentary group, “the pride of permitting the Republic to take a giant step toward equal rights and complete a battle of 30 years.”

The main citizen organization fighting same-sex marriage, Demo for All, called on its supporters not to give up. It sponsored a “citizen vote” — a novel form of protest — in front of the National Assembly as the favorable tally was being recorded and vowed to continue challenging the law in the courts and on the streets.

The lay opposition was backed by France’s main Roman Catholic, Protestant, Muslim, Jewish and Buddhist clerical authorities, who testified in a rare joint appearance before a parliamentary commission. But the vocal protests and street demonstrations came from the main conservative political coalition, the Union for a Popular Movement, and from Demo for All, as religious leaders sought to keep their distance.

Conservative opponents in the National Assembly introduced 4,999 amendments as a delaying tactic, and all of them were beaten down during 110 hours of parliamentary debate spread over 10 days and nights. The often raucous debate ended at 5:40 a.m. Saturday. Although passage was never in doubt, conservative leaders said the marathon was necessary to register their opposition and give voice to a broad disapproval across French society.

Philippe Gosselin, a member who helped lead the Union for a Popular Movement’s opposition in parliament, acknowledged the Socialist victory, but he suggested that even after passage the law could face constitutional challenges. “There are real legal flaws,” he said in a television interview after the vote. “This is a match that is not yet over.”

Although widely opposed in the traditionalist countryside and small towns, same-sex marriage has gained a small majority in most opinion polls in recent months. In view of that, opposition political leaders said that even if they return to power, they are unlikely to try turning back the clock.

President Francois Hollande had put same-sex marriage and adoption by gay couples on the list of promises that helped lead to his election in May. His Socialist Party portrayed the measure as a question of civil rights, calling it “marriage for all” and asking why gay men and women should be deprived of the right to marriage and parenthood enjoyed by straight couples.

In making the change, the Socialists argued, France is only bringing its law in line with other progressive countries in Western Europe and beyond. Seven European countries, including heavily Catholic Spain and Portugal, have already authorized same-sex marriage.

In the United States, where marriage is a matter of state law, the District of Columbia, Maryland and eight other states have approved same-sex marriage, but a large part of the country remains divided on the issue. The U.S. Supreme Court agreed in December to hear a case challenging a state’s right to refuse marriage to gay couples.

Gay rights groups in France, backed by a number of left-wing Socialist Party figures, also have demanded that female couples have the right to medically assisted reproduction, which is carefully limited to certain married couples under current French law. But that issue, on which Hollande reportedly has personal doubts, was put off until consideration of a new family law promised later in the year.