Thomas Merrill, a private practitioner who specializes in human development, also said he had reviewed 50 studies involving same-sex relationships and that not enough data exists to determine how children raised in such unions turn out.

Dan Foley, local co-counsel for the three couples who sued the state in 1991 for the right to marry, cross-examined Merrill about the role of data in whether same-sex couples should be allowed to have children.

"No," Merrill said.

Deputy Attorney General Rick Eichor objected to the question, saying Foley was trying to inflame the trial. But Circuit Court Judge Kevin Chang, presiding over the nonjury trial, allowed Merrill to answer.

Merrill also said under cross-examination that two parents in a home were better than one and that the sexual orientation of a parent was not an indication of the parent's fitness.

Merrill was the state's last witness, putting the case in the hands of the attorneys for the three same-sex couples, who will present four witnesses next week.

A second state witness to oppose homosexuality on moral grounds testified yesterday that most studies on children of gay and lesbian parents were biased.

Richard Williams, Brigham Young University psychology professor, yesterday faulted the methodology in nine studies on the subject and said the results were shaped to validate same-sex families.

But Evan Wolfson, co-counsel for the three same-sex couples, said Williams was the biased one with no expertise in the field of children of homosexuals or heterosexuals.

"He came into court not for scientific reasons, but because of a personal ax to grind," said Wolfson.

During Wolfson's cross-examination, Williams said he was morally opposed to homosexuality, described sociology as unscientific and said he didn't think that science could prove evolution.

A previous state witness, David Eggebeen, a Pennsylvania State University sociology professor and demographer, also said he opposed homosexuality on moral grounds.

Eichor called Wolfson's reaction "classic religious bigotry," saying Wolfson didn't like Williams because he was a Mormon.

"His (Williams') testimony was objective, he gave credit to the studies and he was not the only person to criticize them," Eichor said.

Eichor said the witnesses had proved what the stated wanted to prove: that children were best raised by their biological parents.

"I'm confident at this point that we're winning the case," he added.

To win the same-sex marriage trial before Circuit Judge Kevin Chang, the state must offer a reason compelling enough to justify the sex-discrimination the state Supreme Court has identified in the state marriage law.

Eichor has argued that promoting the optimal development for children is a compelling reason.

He said Chang must determine if the state's argument rises to compelling, a high legal standard.

Wolfson said the state had not provided a compelling reason, adding that it was offensive to suggest that one kind of family was the best.

He said the state's witnesses have supported the case for same-sex marriage, agreeing that no evidence exists to show that same-sex parents aren't fit or loving.

He said they also agreed no evidence exists to deny gay people the right to adopt children.

Eichor said the same-sex-marriage issue hangs between the rights of individuals and the interest of society to set limits for society's protection.