As they reel from a succession of defeats in courtrooms and legislatures, opponents of same-sex marriage have a new chance this week to play one of their most emotional and, they hope, potent cards: the claim that having parents of the same sex is bad for children.

In a federal court in Detroit starting Tuesday, in the first trial of its kind in years, the social science research on family structure and child progress will be openly debated, with expert testimony and cross-examination, offering an unusual public dissection of the methods of sociology and the intersection of science and politics.

Scholars testifying in defense of Michigan’s constitutional ban on same-sex marriage aim to sow doubt about the wisdom of change. They brandish a few sharply disputed recent studies — the fruits of a concerted and expensive effort by conservatives to sponsor research by sympathetic scholars — to suggest that children of same-sex couples do not fare as well as those raised by married heterosexuals.

That view will be challenged in court by longtime scholars in the field, backed by major professional organizations, who call those studies fatally flawed. These scholars will describe a near consensus that, other factors like income and stability being equal, children of same-sex couples do just as well as those of heterosexual couples.