A recent study on the psychological adjustment of 17-year-olds raised in families with lesbian mothers reveals that lesbian mothers raise better-adjusted, happier kids than heterosexual families. Sort of.

The study, published in the June 2010 edition of the journal Pediatrics, got plenty of press this summer. That’s partly because of its shock value and partly because it’s the most complete long-term study made of children raised in same-sex homes. Its researchers followed a group of 78 children conceived through artificial means by lesbian couples and, in some cases, by single lesbian mothers. They concluded that, according to their mothers’ reports, the 17-year-old daughters and sons of lesbian mothers rated significantly higher in social, school/academic and total competence, and significantly lower in social problems, rule-breaking and aggressive behavior than their age-matched counterparts.

The study has been criticized on several grounds. The diagnostic tool used to evaluate the children’s competence and behavior was the Achenbach Child Behavior Checklist, a survey in which parents are asked to evaluate their children’s development and behavior. Some of the questions involve objective considerations, such as whether or not a child wets the bed, but most of them involve subjective judgments. For example: Does the parent believe the child is better than other children at sports?

The Achenbach system ordinarily compensates for its weaknesses by using reports from a variety of sources — usually the parents, the children and a teacher. In the study of children raised by lesbian mothers, only the parents’ reports were used.

The mothers were, for good reasons, not culled from a typical cross section of the population in terms of race, income or education level: Women who are able to afford artificial conception are generally white, university-educated and affluent. This flaw could have been mitigated by using a similarly composed control group. It was not.

Some critics have also raised concerns that one of the study’s authors, Nanette Gartrell, is herself a lesbian and that the study was funded by LGBT advocacy groups. These are legitimate concerns; however, they point toward a larger problem with the use of sociological science as a tool to investigate politically explosive issues. The truth is, similar complaints can be lodged, and routinely are lodged by the homosexual community, against research backed by groups like Narth (the National Association for Research and Therapy of Homosexuality) and Focus on the Family.

Statistics and sociological studies on politically charged issues are almost necessarily biased. Even if the researchers themselves don’t have an ax to grind, studies require the cooperation of a number of interests. The easiest sources of funding are advocacy groups in general, and, although such groups may not put direct pressure on researchers, they do tend to direct their funding toward projects that are likely to produce the results that they want. You are unlikely to find a study funded by the Protestant ex-gay organization Exodus International showing that homosexuality is an innate and immutable trait. Nor are you likely to find research supported by Planned Parenthood demonstrating that abortion causes long-term psychological damage to women.

In the unlikely event that objective researchers can find funding from a disinterested source, there is still the problem of participant bias. Sociological research generally relies on self-reporting; what is measured is strongly conditioned by the way a group of people see themselves — or want to be seen by researchers.

Finally, there is the issue of publication. A century ago, a respectable journal would have taken a massive political risk in presenting a study suggesting that homosexuality was healthy or acceptable. Today, the weight of political censure has shifted, but it is just as strong.

So, what do we do? I think we should honestly admit, at least to ourselves, that our objections to same-sex parenting don’t have solely to do with the psychological adjustment or self-esteem of kids raised in gay and lesbian homes. Nor does our resistance really have to do with a child’s alleged need to be raised by parents of both sexes. Most Catholics are fairly comfortable with the idea of orphaned children being raised by single-sex religious communities, a practice the Church has supported for most of the Christian era. Moreover, the objections against LGBT parenting would not evaporate if the children were being raised in bisexual, polyamorous homes with two mommies and two daddies providing an appropriate gender balance.

The real reason we object: Same-sex unions fail to reflect the whole truth about the meaning and nature of human sexuality. They present significant obstacles, for both the parents and the children, to full participation in the mysteries of Christian salvation.

Our objection to two-mommy and two-daddy households has little to do with sociology, and it is disingenuous to pretend otherwise. Let the behavioral researchers conclude what they will. We know the rest of the story.

Melinda Selmys is the author of Sexual Authenticity:

An Intimate Reflection on Homosexuality and Catholicism (OSV, 2009).