Portugal's President Anibal Cavaco Silva has said he forwarded a gay marriage bill to the nation's Constitutional Court because he has “doubts” about its constitutionality, Portugal's Jornal de Noticias reported.

Speaking to reporters Friday, Cavaco Silva said he forwarded four out of five of the bill's articles to the Constitutional Court because “he had doubts about its constitutionality.”

But he did not respond when asked why he did not include Article 3, which would ban adoption by married couples.

Portugal's Socialist-controlled Parliament, led by Prime Minister Jose Socrates, approved on February 11 the bill that gives gay and lesbian couples the right to marry but prohibits adoption. The court has 25 days to rule on the matter.

The president, who opposes the legislation, had the option of signing the bill, vetoing it or forwarding it for review by the Constitutional Court. He forwarded the bill on March 13, according to an official statement.

While proponents have expressed confidence that the bill is constitutional, others point to a narrow 2009 high court ruling that denied a lesbian couple the right to marry, despite a provision in the constitution that bans discrimination on the basis of sexual orientation.