During the Supreme Court arguments in the Proposition 8 case last week, there seemed to be some confusion about the social science evidence concerning same-sex parents and their ability to raise children. Justice Anthony Kennedy commented that the plaintiffs are asking the court "to go into uncharted waters" with their advocacy of marriage for, and parenting by, same-sex couples. Justice Antonin Scalia remarked that "there's considerable disagreement among sociologists as to what the consequences of raising a child in a single-sex family, whether that is harmful to the child or not."
But there is nothing "uncharted" about gay and lesbian couples raising children. They have been doing that for decades; indeed, 6 million Americans (children and adults) have at least one gay or lesbian parent. Nor is there any "disagreement" among the experts about what the research says about the parenting of these couples. Credible research studies have consistently shown that gay men and lesbians are no less fit than heterosexual parents to raise children, and that their children are no less psychologically healthy. In short, the claim that gay and lesbian parents cause harm to children is completely unsupported by valid scientific evidence.
Studies that have directly compared gay and lesbian parents with heterosexual parents have consistently shown that the former are as fit and capable as the latter, and that their children are as psychologically healthy and well-adjusted. A 2001 comprehensive survey of peer-reviewed scientific studies concluded that the evidence from empirical research "shows that parental sexual orientation per se has no measurable effect on the quality of parent-child relationships or on children's mental health or social adjustment." A more recent review by the same authors noted "the ubiquitous findings of no differences" in comparisons of the families of heterosexual couples with those of lesbian or gay couples. These conclusions are bolstered by three recent studies using national representative samples: one using data from the National Longitudinal Study of Adolescent Health, another using data from the from the Early Childhood Longitudinal Study (Kindergarten Cohort), or the ECLS-K, and the third using U.S. Census data.
After careful scrutiny of decades of research, the American Psychological Association concluded in 2004 that "there is no scientific evidence that parenting effectiveness is related to parental sexual orientation: lesbian and gay parents are as likely as heterosexual parents to provide supportive and healthy environments for their children," and that "research has shown that the adjustment, development, and psychological well-being of children is unrelated to parental sexual orientation and that the children of lesbian and gay parents are as likely as those of heterosexual parents to flourish." Similarly, the American Academy of Pediatrics has adopted a policy statement that states:
Scientific evidence affirms that children have similar developmental and emotional needs and receive similar parenting whether they are raised by parents of the same or different genders. If a child has 2 living and capable parents who choose to create a permanent bond by way of civil marriage, it is in the best interests of their child(ren) that legal and social institutions allow and support them to do so, irrespective of their sexual orientation.
The National Association of Social Workers, the American Psychoanalytic Association, the American Psychiatric Association and the American Medical Association have all adopted similar policy statements in support of same-sex parenting and marriage.
Those who have challenged the unanimous findings of these national organizations have largely based their disagreement on the "Regnerus study," which compared child development outcomes across a range of family types, including two types that were misleadingly characterized as "lesbian mother" and "gay father" families. This study's design precludes any meaningful conclusions because of its faulty definition of children raised by gay or lesbian parents and its conflation of family instability with any potential effects of parental sexual orientation. Regnerus conducted an Internet survey to identify adults who reported believing that at some time in their childhood, their mother or father had "ever ha[d] a romantic relationship with someone of the same sex." These individuals were placed into the categories of "LM" (lesbian mother) or "GF" (gay father). But these categories were not confined to people who were actually raised by gay and lesbian parents, let alone by same-sex couples. Indeed, most participants in these groups spent very little, if any, time being raised by such a couple. These participants, with widely varying family circumstances, were then compared with another group of people who were raised in stable two-parent families with heterosexual parents. The methodological flaws in the study led an independent auditor appointed by the journal that published the study to describe it as "a non-scientific study" and conclude that it should not have been published. Over 200 scientists, clinicians and academics signed a letter to the journal's editorial board commenting on the study's scientific deficiencies.
So the reality is that marriage and parenting by gay and lesbian couples are neither novel nor "uncharted," to borrow Justice Kennedy's phrase. The facts are beyond any serious dispute: The abilities of gay men and lesbians as parents and the positive outcomes for their children are not areas where credible scientific researchers disagree. To doubt the ability of same-sex couples to raise children is to ignore decades of scientific study and the consensus of the relevant experts. More importantly, millions of children are already being raised in gay and lesbian households. Those children would benefit greatly from marriage and the benefits it brings. Even the Proposition 8 proponents' lead expert witness at trial admitted that allowing same-sex couples to marry "would improve the happiness and well-being" of gay and lesbian couples and their children. The Supreme Court should consider the welfare of these children, in light of the undeniable scientific consensus, and hold Proposition 8 unconstitutional.