LDS Church officials are urging California Mormons to "do all you can" to support a constitutional amendment to recognize only marriages between a man and a woman.
The call to action came from the First Presidency of The Church of Jesus Christ of Latter-day Saints in a letter that is scheduled to be read to local California congregations, church spokesman Scott Trotter said.
"The church's teachings and position on this moral issue are unequivocal," the letter reads. "Marriage between a man and a woman is ordained or God, and the formation of families is central to the creator's plan for his children.
"Children are entitled to be born within this bond of marriage."
Last month, the California Supreme Court overturned a voter-approved law outlawing gay marriage. After that ruling, Affirmation, a support group for gay and lesbian Mormons, had urged the LDS Church to stay out of the political debate over the proposed constitutional amendment, which would overrule the state's high court.
"We believe in respect for all families," said David Melson, senior assistant executive director of Affirmation.
"We are extremely disappointed in their action," Melson said. "This is a matter of civil marriage. It doesn't affect religious marriage."
Back in 2000, the LDS Church was active in urging California residents to ban gay marriage through a public referendum.
Proposition 22 was designed to prevent formal sanction of same-sex marriages performed in other jurisdictions from gaining future legal recognition on par with traditional marriage. Voters approved the measure, with 61 percent in favor and 39 percent opposed.
Now voters are trying again, this time through a state constitutional amendment.
In the letter, LDS Church President Thomas S. Monson and his counselors, President Henry B. Eyring and President Dieter F. Uchtdorf, said, "Our best efforts are required to preserve the sacred institution of marriage."