Bishop James Conley, the apostolic administrator of the Archdiocese of Denver, has called a proposed bill that would recognize the relationships of gay and lesbian couples with civil unions “dangerous and unjust.”

“We do not know the long-term consequences of creating a parallel for marriage, distinct from its ancient and natural meaning. But we do know they will be severe,” Conley said in a January op-ed titled Make No Mistake: Civil Unions Are An Effort To Redefine Marriage published in the Denver Catholic Register.

Gay couples can currently enter a civil union in Illinois, New Jersey, Rhode Island, Delaware and Hawaii.

“The Catholic Church doesn't teach that persons who experience homosexual inclinations are evil – quite the contrary, in fact,” Conley wrote. “But our church does believe that homosexual attraction is a tragic distortion of the great gift of sexuality God has given us. And civil-union laws endorse and sanction that distortion by suggesting that homosexual relationships are equivalent to marriage.”

Conley went on to urge Catholics to join a Colorado Catholic Conference campaign opposing the move.

Opposing the bill “protects children, protects marriage and, ultimately, protects the common good of all of us.”

Last year, a civil unions bill died in a Republican-controlled House committee after the Senate had approved the measure. Colorado voters approved a constitutional amendment banning gay marriage in 2006.

The bill is expected to be reintroduced this year.

(Related: Group of Colorado Republicans endorse civil unions for gay couples.)