A majority of Utah state legislators are urging the Supreme Court to to take up a case challenging the state's ban on marriage for same-sex couples and reverse a recent ruling by a federal appeals court that found the ban unconstitutional.

Eighty members of the state legislature — 22 members of the 29-person Senate and 58 members of the 75-person House — signed on to an amicus brief filed in the case, Herbert v. Kitchen, in which they argue marriage should be preserved as between on man and one woman and that if same-sex couples are allowed to marry, it will lead to incestuous and polygamous marriages.

"[T]he Tenth Circuit did not adequately consider the consequences of its decision for Utah's prohibitions of polygamous and incestuous marriages," the brief states. "If the choice of marriage partners is an unlimited fundamental right ... and if that marriage choice cannot be denied even when a majority believes that choice to be "immoral," ... then the fundamental rights analysis applied by the Tenth Circuit will apply with even greater force to consenting adults desiring polygamous marriage or marriage between at least some close relatives. The prohibition of those marriages has always been grounded in morality."

As such, the lawmakers tell the justices, "The Tenth Circuit's fundamental rights analysis abandons all standards of morality in marriage laws, which would then improperly justify forced state endorsement of polygamous and adult incestuous marriage throughout the United States."

The argument is among many the lawmakers make in the brief in defense of the state's marriage ban. Additionally, they say states should have the authority to determine such laws, and "the State's carefully crafted statutory scheme" of marriage only between a man and a woman best supports children.

On June 25, the 10th Circuit Court of Appeals ruled Utah's ban on marriage for same-sex couples is unconstitutional. Utah Gov. Gary Hebert and Attorney General Sean Reyes have asked the Supreme Court to take up the case and consider their appeal of the matter, and it was that request that led to the lawmakers' filing.