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Supreme Court of Iowa




The plaintiffs in this case met their burden of demonstrating the irrationality of Iowa’s statutory exclusion of same-sex couples from marriage. They did this, in part, by presenting social science research regarding the irrelevance of sexual orientation to parental ability and the psychological and social well-being of children raised by same-sex parents. In addition to arguing that the marriage exclusion is irrational, the plaintiffs also alleged that the exclusion should be subject to heightened scrutiny because it violates the fundamental right to marry and discriminates on the bases of gender and sexual orientation. Amici agree that the exclusion of same-sex couples from marriage should be subject to heightened scrutiny for those reasons. In this brief, however, amici focus exclusively on why the trial court appropriately relied on social science research in concluding that the exclusion is not rationally supported by state interests relating to children.

In particular, amici explain that it is well settled that courts may rely on social science research to help resolve constitutional issues and that the presentation of such evidence may play an important rule in determining so-called “constitutional” or “legislative” facts. In this case, the mainstream scientific and child welfare community as well as many other courts have accepted the research presented by the plaintiffs as valid. In considering that research, the trial court properly found that it negated the state’s asserted justifications for the marriage ban. The trial court also properly declined to admit expert evidence that did not meet the standard in Iowa Rule of Evidence 5.702.

Although this case involves constitutional issues that are subject to de novo review, this Court should take the trial court’s findings into account and should reject the arguments of the State and certain amici that these findings are not entitled to any weight. See Def.’s Br. at 44; Proof Br. of the National Legal Foundation as Amicus Curiae at 3-10; Br. of United Families International as Amicus Curiae, at 23-25; Br. of Iowa Legislators (the “Iowa Legislators Br.”) at 18-25. Under any standard of review, this Court should adopt the trial court’s findings because they are supported by reliable research and by the unanimous consensus of mainstream medical, psychological, and child welfare organizations, as well as by the prior family law decisions of this Court.

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