Lawrence and Garner were arrested for having sex in 1998

The case was brought by two Texas men, John Lawrence and Tyron Garner, who were caught having sex on private premises in 1998.

On Thursday, Justice Anthony M. Kennedy said for the majority of the judges in the 6-3 ruling that the two men "are entitled to respect for their private lives".

BBC News Online's Washington correspondent Steve Schifferes says the ruling is likely to make laws that still regulate sodomy illegal, and provide an important assurance for the 600,000 openly gay households in the country.

All of us as Americans have the right to choose how we can express our love for one another in the privacy of our own homes Ruth Harlow The men's lawyer

Gay rights and civil liberties groups hailed the ruling as "historic", but there was an outcry from conservatives who said it was an attack on the family and the "moral norms" of the nation.

Matt Foreman, director of the National Gay and Lesbian Task Force said: "It's saying to everyone all across the country that the government has no right peering behind your bedroom door or knocking it down and arresting you."

But Tom Minnery, of the conservative Focus on the Family, said: "If the people have no right to regulate sexuality then ultimately the institution of marriage is in peril, and with it, the welfare of the coming generations of children."

'Right to choose'

Thursday's decision reversed a ruling 17 years ago that US states could punish homosexuals for engaging in sex with consenting adults.

Justice Kennedy said: "The state cannot demean their existence or control their destiny by making their private sexual conduct a crime," he said.

Ruth Harlow, the lawyer for the two men, hailed the verdict as the one which recognises the "basic humanity" of gay and lesbian Americans.

ANTI-SODOMY STATES Alabama, Florida, Idaho, Louisiana, Mississippi, N.Carolina, S.Carolina, Utah, Virginia - ban sodomy between consenting adults Texas, Kansas, Oklahoma, Missouri - ban gay couple sex

"All of us as Americans have the right to choose how we can express our love for one another in the privacy of our own homes," she said.

"The court is just catching up with American society, which has made major progress," the lawyer added.

Mr Lawrence and Mr Garner were arrested after a neighbour falsely reported that a man with a gun was "going crazy" in Mr Lawrence's apartment.

The neighbour was convicted of filing a false report, but Mr Lawrence and Mr Garner were arrested, jailed overnight, and fined $200 each plus court costs.

'Protecting marriage'

They have argued that the state's law unfairly infringes their right to privacy and to the equal protection of the law.

During the case, Texas defended its sodomy law by saying it helped to protect marriage and child-rearing.

HAVE YOUR SAY I don't see how this doesn't strike down every anti-sodomy law in the US Sam, US Send us your comments

The state argued that the sodomy "has nothing to do with marriage or conception or parenthood and it is not on a par with these sacred choices".

On Thursday Justice Antonin Scalia, who wrote the opinion for the three dissenting judges, said "the court has largely signed on to the so-called homosexual agenda".

"The court has taken sides in the culture war," Justice Scalia said, but added that he personally had "nothing against homosexuals".

Supporters of the ban also argue that the court's ruling would eventually lead to allowing same-sex marriage in Texas.

The verdict will present difficulties for President George W Bush, according to the BBC's Justin Webb in Washington, as he will have to comment on what is occurring in his home state.

If he appears to condone homosexuality he will horrify many of his core supporters but if he backs the Texas law his hopes of winning more liberal suburban votes in next year's presidential elections could be damaged, our correspondent says.

Thirteen US states still officially outlaw private oral or anal sex between consenting adults, compared to nearly all states 50 years ago.

Of those, four - including Texas - ban oral and anal sex between same-sex couples.

In the last four decades, the US Supreme Court has established a right of privacy that extends to a range of sexual conduct - including the right to contraception and abortion, even for unmarried couples.