Lawyers for gay couples told the Arkansas Supreme Court on Thursday that a policy banning homosexuals from becoming foster parents is unconstitutional, but the state argued that it protects children's moral and spiritual welfare.

Because the state has banned gay marriage, and its Child Welfare Agency Review Board bars unmarried couples who live together from becoming foster parents, gay couples cannot have foster children, said Kathy L. Hall, attorney for the Department of Health and Human Services.

The state is appealing a 2004 lower court decision that found the welfare board's 1999 ban to be unconstitutional.

The state's utmost concern is the health, safety and welfare of foster children, "and that can't happen in a home where unmarried sex occurs," Hall said.

Justice Annabelle Clinton Imber pointed out that the state allows single heterosexual individuals to be foster parents, but not single homosexuals. Hall said that unlike homosexuals, a single heterosexual parent "has the potential" to find a spouse.

"So you're saying ... the agency is also going to be asking a heterosexual how they behave in the bedroom," Imber said.

Leslie Cooper, attorney for the American Civil Liberties Union, argued that the state's policy is discriminatory and "couldn't possibly do anything to protect the interest of children."

The ban hurts children, she said, by reducing the number of eligible foster parents.

Four Arkansans sued over the policy, saying homosexuals who otherwise qualified as foster parents had been discriminated against. They contend the ban violates their right to privacy and equal protection under the state and U.S. constitutions.