MADRID, June 30 - The Spanish Parliament gave final approval today to a bill legalizing same-sex marriage, making Spain only the second nation to eliminate all legal distinctions between same-sex and heterosexual unions, according to supporters of the bill.

The measure, passed by a vote of 187 to 147, establishes that couples will have the same rights, including the freedom to marry and to adopt children, regardless of gender.

"Today, Spanish society is responding to a group of people who have been humiliated, whose rights have been ignored, their dignity offended, their identity denied and their freedom restricted," Prime Minister José Luis RodÃguez Zapatero told Parliament.

Spain is the fourth country to legalize gay marriage, after Canada, Holland and Belgium.

But only Canada's law, which was extended nationwide by Parliament this week, contains language as liberal as Spain's, according to gay marriage advocates.

The Spanish measure simply adds one sentence to existing law: "Marriage will have the same requirements and results when the two people entering into the contract are of the same sex or of different sexes."

The laws in Holland and Belgium, by contrast, create a separate category of rights for same-sex couples that fall short of full equality on issues like adoption, these advocates say.