For the first time in the United States, same-sex couples have been married in legally-binding, state-sanctioned ceremonies. Gay couples are marrying in the northeastern state of Massachusetts, but the highly-divisive issue is far from decided on a national basis.

At just after nine in the morning local time, Massachusetts made history as two women together for 18 years, exchanged marriage vows in a civil ceremony near Boston. Other same-sex couples followed, the start of what is expected to be a flurry of such ceremonies for gay couples.

It was only a few hours earlier that a state supreme court order mandating same-sex marriage went into effect. Some couples had lined up outside city hall more than a day in advance to be able to fill out marriage-license applications at the stroke of midnight.

Among hundreds of couples applying were Marcia Hams and Susan Shepherd. Speaking on NBC's Today program, Ms. Shepherd said the battle for same-sex marriage is a matter of equal rights and societal recognition.

"It is really about respect. Respect for our relationship and the relationships of other gay people," she said. "Marriage is the way that relationships are respected in this culture. And we do not see why we cannot have that same respect."

But not everyone feels society should sanction or confer benefits upon same-sex relationships. Jordan Lawrence of the anti-gay marriage organization, Alliance Defense Fund, said it is a mistake to allow same-sex couples to marry.

"This is an attack on something that has been a consensus of world culture since the dawn of time, that societies are best ordered with marriage defined as one man and one woman," he said.

Opponents of gay marriage waged a furious and ultimately unsuccessful effort in federal court to block the ceremonies until voters in Massachusetts can have their say. Last week, the U.S. Supreme Court declined to intervene on the matter.

Earlier this year, Massachusetts' legislature took the first step to amend the state constitution to ban gay marriage, but the question cannot be put to voters until 2006.

It is not yet clear what impact gay marriage in Massachusetts will have on the nation. Numerous states have passed laws banning same-sex marriage and declaring that those performed by other states will not be recognized.

Some legal scholars believe those laws will be challenged in court by gay couples who secure marriage licenses in Massachusetts or elsewhere and relocate to states where same-sex marriage is banned.

The Massachusetts ruling prompted officials in San Francisco, upstate New York, and Portland, Oregon, to issue marriage licenses as acts of civil disobedience earlier this year.

President Bush has said that, ultimately, the matter may have to be decided by amending the U.S. constitution so as to define marriage solely as between a man and a woman.

Public-opinion polls show most Americans oppose same-sex marriage, but also show a majority do not want to alter America's founding document to decide the issue.