Joseph Price of Brigham Young University repeatedly complimented the work of Stanford University sociologist Michael Rosenfeld, but he came up with a different conclusion.
Price said children raised by a father and a mother had a 35 percent higher chance of moving from grade to grade than children of same-sex couples.
"The ideal environment for a child is to be raised by a father and a mother," preferably a married couple, he said.
Price testified for the state of Michigan on the sixth day of trial over the future of a ban on gay marriage. Two Detroit-area nurses who want to marry and jointly adopt each other's children are asking a judge to overturn the 2004 constitutional amendment.
The key issue for U.S. District Judge Bernard Friedman: Is there a rational public interest in restricting marriage to a man and a woman?
The trial should end Friday. It has been dominated by testimony from social scientists and other experts about research—or a lack of research—on children and same-sex households.
Rosenfeld, testifying last week for Jayne Rowse and April DeBoer, said children of same-sex couples are as likely to make normal progress through school as children from other families.
But Price said Rosenfeld should have used a larger pool of children. He said the outcome would have been much different.
On cross-examination, attorney Dana Nessel sharply challenged Price's claim that an ideal household is one led by a man and a woman. She asked him what Rowse and DeBoer should do with their three adopted children who have special needs.
"Not every child has the ability to have that ideal environment, correct?" Nessel asked.
Price replied: "It doesn't change what the ideal environment is."
Earlier, attorneys for the couple tried to peck away at the credibility of a social scientist who is the author of a disputed study of young adults who grew up in a home where a parent had a same-sex relationship.
Mark Regnerus of the University of Texas said his study found they were likely to have more problems with finances and education than children raised by a mother and a father.
Christine Williams, chairwoman of the school's sociology department, said the department doesn't share Regnerus' views.
"Nor do they reflect the views of the American Sociological Association, which takes the position that the conclusions he draws from his study of gay parenting are fundamentally flawed on conceptual and methodological grounds," Williams wrote on the department's website while Regnerus was in Detroit.
Regnerus was asked about the statement while on the witness stand and said it was "sad" and "regrettable."
"I guess they've been getting negative press about my appearance," he said of the university.
Follow Ed White at http://twitter.com/edwhiteap