Maltese Bishop Charles Scicluna told the Times of Malta that he spoke with Pope Francis about the bill and the Pope encouraged him to speak out against it.
The Holy See’s reaction may come as a surprise to those who have viewed him as progressive on gay rights.
LGBT magazine ‘The Advocate’ even named him their person of the year, citing his comments about homosexuals. “Who am I to judge a gay person of goodwill who seeks the Lord?” he told reporters in Italian in July.
Despite his July comments, the Pope has a long history of being against gay rights.
He has come out strongly opposed to same-sex marriage and called it “a destructive attack” on God’s plan.
Lawmakers in Malta introduced a bill in the autumn to allow civil unions and same-sex adoptions.
The legislature is expected to continue debating the proposed law in the coming year.