In our day, the alleged personal liberation of the sexual revolution is becoming progressively socialized in institutions and norms. As a result, we have moved beyond the cultural condition in which scientific research into the related social behaviors (hormonal contraceptive use, premarital sex, abortion, homosexual relations, gender transformation) is deployed for political ends, into a state in which the process of deciding scientific truth has itself become irretrievably politicized. In this new situation, the end does not merely justify the means, it becomes the means. What advances the desired political agenda becomes the new criterion of truth.

Thus, social scientists who present evidence that the behaviors of sexual liberation are not harmful—in same-sex parenting research, this is couched as “no differences” from heterosexual parents in child well-being—do not merely claim that their conclusions are strong while contrary findings are weak. Instead, they claim that their conclusions are the only permissible ones, while contrary findings are necessarily unscientific. In their minds, contrary evidence either does not exist, or it must reflect pseudo-scientific bias.

In his meticulously researched new book, Same-Sex Parenting Research: A Critical Assessment, Walter Schumm, Professor of Family Studies at Kansas State University, turns this scenario on its head. In research on the politically charged question of the well-being of children in the care of same-sex parents, social scientists and their associations have emphatically asserted unqualified and universal support for the finding of “no differences.” Research that does not find this conclusion, they assert, simply cannot be credible or methodologically sound. Some deny the contrary research even exists. “It has not been unusual,” Schumm writes, “for at least some scholars in this area to make statements such as, ‘Not a single study has ever found any results that indicated children of same-sex parents to be any different from children of heterosexual parents in any way.’” These “absolute claims were made in an attempt to impress courts with the utter harmlessness (no ‘difference’ = no harm) of gay and lesbian parenting in order to promote the legalization of same-sex marriage.”

And yet, as Schumm proceeds to show, by the traditional canons of scientific reason and inference, such claims are manifestly false.

Science vs. Dogma

The bulk of the book consists of chapters examining the specific areas in which “no difference” is claimed. These include family stability, sexual abuse and other negative behaviors among parent couples, and child outcomes relating to sexual orientation, gender identity, gender roles, and mental health. Through a detailed review of virtually all extant research in each area, Schumm demonstrates decisively that contrary evidence not only exists, it is abundant and methodologically strong.

Almost none of the studies claiming to find “no differences” actually does so.

Moreover, he shows, almost none of the studies claiming to find “no differences” actually does so. Most violate or ignore basic requirements of scientific evidence, such as using a random sample, not letting participants know the political implications of the study, and accounting for mothers’ desire to make their children look good (“social desirability bias,” in sociology-speak). Many of the politically correct studies that report “no differences” actually do find differences. These are often buried deep in their data tables or technical analysis, but they do not escape Schumm’s gimlet-eyed scrutiny.

Schumm’s strategy for exposing the weaknesses of the “no differences” research is old-fashioned scholarship: he has simply read more studies, and digested their contents better, than most of the authors whose work he examines. The typical “no differences” review in this field includes about eighty studies. In this book, Schumm includes over 330 studies. The bibliography alone is over thirty pages. Not content to accept results reported by the authors, he reanalyzes the data distributions from the tables of reported statistics found in most studies, to verify—or undermine—the claimed findings of a study. The results are compelling.

For example, in response to an influential, politically correct review of the literature that concluded there were no differences for same-sex-parented children in gender-role behavior (the tendency for boys to do masculine things, or for girls to do feminine things), Schumm notes that the author cited only thirteen papers; he then proceeds to cite nine more on the topic, including three by the author of the review, that contradict the review’s conclusion. On the question of child sexual orientation (whether same-sex-parented children are more likely to develop homosexual attractions or adopt a homosexual identity than children in the general population), Schumm cites thirteen papers that contradict the review’s claim that there are no differences on this front, including two by the author of the review, which were not among the twelve papers the review did cite. He writes:

This type of situation should serve as a warning to the public, to the courts, to scholars, and to students everywhere that just because a famous author publishes a literature review in a major, comprehensive handbook does not imply that it should be automatically accepted as accurate or comprehensive.

Point by point, as Schumm patiently critiques the several hundred studies reviewed in the book, the conviction gradually becomes inescapable that the entire research thesis of “no differences,” trumpeted as an unassailable consensus by some of our society’s most respected arbiters of scientific credibility, is nothing more than a tissue of fabrications and contradictions under color of science. Schumm’s conclusion does not mince words: “The research presented in this book has shredded any pretense that the dogma of ‘no differences’ is factually correct.” He concludes that the “no differences” thesis is not a scientific theory at all, but a dogma. “If dozens of scholarly results won’t convince you otherwise,” he asks, “will anything?”

A Non-Partisan Critique

Consistent with the book’s subtitle (“A Critical Assessment”), Schumm does not compile his devastating critiques of the particular claims that support homosexual marriage into any sort of general case against that idea. For him, the problem with the “no differences” claim is not that it led to gay marriage but that it jettisoned the standards of science. “I am not necessarily saying that courts have made bad decisions,” he writes, “but that they were certainly fed ‘bad’ science, no matter how correct their decisions might have been in the end.”

Indeed, Schumm’s skeptical critique of the research is decidedly non-partisan. He does not hesitate to point out the flaws and limitations in studies, such as those by Mark Regnerus and me, that have reported substantial negative differences for children with same-sex parents. One of his most prominent critical exchanges, outside of this book, has been with Paul Cameron of the Family Research Institute, regarding the latter’s research that is critical of same-sex parents. A reasonable assessment would be that his conclusion in favor of such contrary research, despite his lack of sympathy with its legal and social implications, would lend credibility to his conclusion as one of rare integrity.

For Schumm, it is all part of being an honest scientist. “[A]n honest scientist,” he tell us, “has to be willing to see at least some of his or her most cherished scientific (even religious) theories or beliefs (or other assumptions) be falsified through careful research.” The book concludes with a fervent appeal for more such honesty:

My fondest hope [for the book’s effect] is not that same-sex marriage be declared illegal or same-sex adoption be banned . . . but that perhaps a few persons here and there will have been challenged to think more carefully about scientific research in areas of political controversy and be a little less eager to jump to conclusions that may not in fact be warranted after a careful, detailed, systematic review of the research literature.

In this hope, Schumm has not, I think, fully considered the implications of his findings. If the newly legal social arrangements regarding homosexual relations are not warranted by the research, why would an honest scientist support their continuance?

Political and Scientific Implications

Given the book’s publication by a British traditional marriage advocacy group, I suspect that Schumm may be less troubled than he suggests (perhaps to forestall accusations of bias) by the prospect of repealing gay marriage or adoption laws. Schumm’s progressive critics appear to think so, too. In appendices, he relates the extensive attempts to discredit him, including shunning at professional conferences, difficulty publishing in mainstream journals, and calls for him to be fired because of his views. “Some very Christian scholars,” he reports in the prologue, “have gone out of their way to avoid any association with this book because of the stigma or discrimination they fear.” These cautionary accounts contrast sharply with Schumm’s hope for more fair-minded consideration of the evidence, and ironically confirm his conclusion about the dogmatic nature of the belief in “no differences.”

More importantly, Schumm’s reluctance to follow the political implications of the science in his own research threatens not only the policies involved but also the science. If, as I argue, political expediency is becoming the new criterion of scientific truth for issues of sexual liberation, Schumm’s brilliant analyses are not likely to be accepted by those he critiques, precisely because his appeal to evidence is so strong and fair-minded. This is particularly true when the political ideology being critiqued is that of sexual liberation. While both supporters and deniers of natural law can be blind to contrary evidence or distort science for political ends, those who advocate a sexual ethic unconstrained by the limitations of the body are particularly unlikely to be deterred by a commitment to truth constrained by the limitations of the senses. Those who reject religious or philosophical dissent from the dogma of gay marriage as irrational bigotry are not likely to accept scientific dissent as reasonable and fair-minded.

To concede same-sex marriage in the face of contrary scientific evidence is to concede science itself.

Today, those with religious or conscientious reservations about gay marriage must assert them or risk losing their freedom to make any religious assertion at all. In the same way, those with scientific or evidential reservations must assert them in order to preserve the ability to practice honest science at all. To concede same-sex marriage in the face of contrary scientific evidence is to concede science itself.

For those who are unwilling to make that concession, and are convinced on grounds of science, faith, or principle that the defense of natural marriage is worth making, this book offers an immensely valuable array of evidence and arguments.