Utah argues one reason it is likely to ultimately prevail in reversing legalization of same-sex marriage in the state is the "large and growing body of social science research" that supports its "rational" interest in opposite-sex marriage.
That research, it argues, backs "the importance of providing unique encouragement and protection for man-woman unions" because it shows children do best when raised by their father and mother (whether biological or adoptive) and limiting access to marriage to such unions increases that likelihood.
These are the core "legislative facts" that lawmakers and voters have relied on in limiting marriage to man-woman unions, it says.
"And even when contravened by other evidence, they are not subject to second-guessing by the judiciary without a showing that no rational person could believe them," the state says.
In a footnote, the state says according to other Supreme Court decisions it has no burden to prove that "its views on marriage are correct or sound."
Rather, "the research discussed here briefly sketches what Utah and its citizens could rationally believe about the benefits of limiting marriage to man-woman unions," it says.
A state that allows same-sex marriage "necessarily loses much of its ability to encourage gender complementarity as the preferred parenting arrangement," the application states. "And it thereby substantially increases the likelihood that any given child will be raised without the everyday influence of his or her biological mother and father indeed, without the everyday influence of a father or mother at all."
The state doesn't elaborate on that point.
But Utah observes that in its United States v. Windsor decision, which struck down a provision in the Defense of Marriage Act, the court said states were "constitutionally permitted to decide that this risk is offset, for example, by the risk that children being raised in families headed by same-sex couples will feel demeaned by their families' inability to use the term 'marriage.'"
The state concludes that the Windsor majority "does not suggest and we think the court unlikely to hold after carefully considering the manifest benefits of gender complementarity that a sovereign state is constitutionally compelled to make that choice."
In his decision, Shelby said both sides provided numerous studies about child-rearing in opposite-sex and same-sex households, creating a "factual dispute about the optimal environment for children" which the court could not resolve on motions for summary judgment.
In other words, it's an unsettled issue.
That said, Shelby added he did not need to resolve the question "because the state's argument is unpersuasive for another reason."
"Once again, the state fails to demonstrate any rational link between its prohibition of same-sex marriage and its goal of having more children raised in the family structure the state wishes to promote."