A gay marriage bill before Portugal's Parliament won initial approval on Friday, the BBC reported, but lawmakers have rejected provisions that would allow gay adoption.

Members of Portugal's Socialist Party backed the bill as it faced its first reading. The bill heads to a committee for review before returning for a final vote. Lawmakers say they hope to legalize gay marriage before a May visit by Pope Benedict XVI.

Passage in the Socialist-controlled Parliament is nearly certain, but a presidential veto threatens to prevent the bill from becoming law. President Anibal Cavaco Silva has publicly stated his opposition to granting gay and lesbian couples the right to marry.

Last July, Portugal's Constitutional Court upheld the constitutionality of a gay marriage ban, denying a lesbian couple the right to marry. In a 3 to 2 decision, the court said that while the Constitution outlaws discrimination based on sexual orientation, it does not say gay marriage must be permitted.

After the loss, Prime Minister Jose Socrates, who heads the Socialist Party, pledged to introduce a gay marriage bill if returned to power in the general election, despite strong opposition from the Catholic Church.

Commentators in the Portuguese press have speculated that if Parliament approves the measure, President Silva could possibly forward the issue to the Constitutional Court.

The Vatican condemned the 2005 legalization of gay marriage in neighboring Spain and has called for the ouster of Socialists who supported the law. But the Catholic Church in Portugal has refused to become involved in the issue.

Lisbon's Cardinal Patriarch Jose Policarpo has called marriage “Parliament's responsibility.”

Seven countries – Canada, Norway, Spain, Belgium, the Netherlands, South Africa and most recently Sweden – have legalized gay marriage. Several cities in Latin America recognize gay unions and a gay marriage law approved by lawmakers in Mexico City is expected to take effect in February.