Slovenian lawmakers have approved same-sex marriage and child adoption by gay couples amid opposition from conservative groups and the Catholic Church.

Parliament voted 51:28 Tuesday to pass changes to the family law allowing homosexual couples to marry and adopt children. Slovenia in the past allowed same-sex partnership union, but without the right to child adoption.

Earlier Tuesday, a few thousand people protested at a rally dubbed "Children Are At Stake" to voice their opposition to the changes. Opponents have announced plans to force a referendum on the issue after a similar bid was rejected in a vote three years ago.

Leftist lawmaker Matej Vatovec said the parliamentary support ensured Slovenia will become a "truly tolerant and inclusive community." He said "today Slovenia is entering the 21st century."