Slovenians rejected a law on Sunday that would have let homosexuals adopt children of their partners, preliminary partial results of a referendum showed.
The previous parliament, dominated by a centre-left coalition, included the right in a family law passed in June 2011.
But conservative group the Civil Initiative for Family and Children's Rights opposed the change and forced a national referendum on the issue.
Preliminary results released by the state electoral committee, showed 56.5 percent of voters were against the law while 43.5 percent supported it.
Although the law would not allow gay couples to adopt children from a third party, conservative groups, backed by the Roman Catholic Church, wanted it annulled.
The referendum result is legally binding and prevents the enforcement of the law, which has been on hold since June because of the referendum demand. The government is not allowed to pass a similar law for at least one year.
(Reporting By Marja Novak; Editing by Andrew Heavens)