BOGOTA -- In a historic decision, Colombia's constitutional court has opened the door for same-sex couples to legally adopt children in the conservative South American nation.

In the 6-2 ruling Wednesday, magistrates said adoption agencies can't discriminate against gay and lesbian couples.

Colombia's Roman Catholic Church immediately denounced the decision as violating the rights of children and going against the wishes of the majority of Colombians. Spokesman Juan Vicente Cordoba promised an "emphatic protest" and reiterated the church's demand that the issue be decided by a plebiscite.

President Juan Manuel Santos' government had argued in favour of the plaintiffs in the landmark case. The high court paved the way for Wednesday's decision in February when it authorized adoption rights for gay couples in which one member is a biological parent.