(Adds comment from legal team for plaintiffs In paragraphs 11-12)
By Jennifer Dobner
SALT LAKE CITY, Feb 4 (Reuters) - Utah attorneys seeking to overturn a federal court decision that struck down a state ban on gay marriage have argued in appeals papers that prohibiting same-sex unions is crucial to safeguarding the best interests of children.
The conservative, heavily Mormon state briefly became the 18th U.S. state to allow same-sex marriage when a federal judge ruled in December that a state ban on gay marriage was unconstitutional.
His ruling was put on hold by the U.S. Supreme Court, but not before about 1,400 gay couples had tied the knot.
The outcome of Utah's appeal of the decision could, if it reaches the U.S. Supreme Court, see the high court rule on the constitutionality of bans on gay marriage that are now in effect in most states.
"As between mutually exclusive models of marriage, the man-woman model is simply the one the state and its people believe is best for children," Utah state attorneys said in filings submitted late on Monday to the 10th U.S. Circuit Court of Appeals.
The court brief argued that risks to children from same-sex marriage include the emotional toll of growing up without a father or mother because their parents would be of the same gender. It also suggested birthrates in Utah might decline due to adults opting for same-sex unions instead of procreating.
A hearing in the case is expected on April 10 in Denver.
Cliff Rosky, a University of Utah law professor who sits on the board of gay rights group Equality Utah, said the state's arguments were demeaning to families headed by same-sex couples.
He said the American Pediatric Association and American Psychiatric Association and similar groups reject the contention that gay parents do not raise healthy, well-adjusted children.
"These are the same arguments that states have been using to defend same-sex marriage bans for 40 years," Rosky said.
Shannon Minter, legal director of the National Center for Lesbian Rights, which is co-counsel for the plaintiffs challenging the ban, pointed out Utah's legal brief acknowledged same-sex couples can be good parents.
"The law should support all families, not make it harder for some families to take care of themselves and their children," Minter said in a statement.
U.S. District Court Judge Robert Shelby's ruling invalidating Utah's ban on gay marriage, which was passed by voters in 2004, found it violated gay couples' rights to due process and equal protection under the U.S. Constitution.
The ruling jolted many of Utah's 2.8 million residents, nearly two-thirds of whom are members of The Church of Jesus Christ of Latter-day Saints, which teaches that traditional marriage is an institution ordained by God.
Little more than a decade ago, none of the 50 U.S. states recognized same-sex marriage. Since then, attitudes have changed rapidly in some parts of the country. (Writing by Alex Dobuzinskis; Editing by Cynthia Johnston and Mohammad Zargham)