Lesbian Parenting and the Problem With Public Information
The conclusion does not strike me as particularly surprising. In our society and many others, mothers play a larger role in child rearing than fathers, so it would not be surprising if children with two mothers did, on average, better than children with a mother and a father. Reading the story, however, I concluded that it did not actually give me much reason to believe in its conclusion—for two related reasons.
The first was a quote from the lead researcher that appeared in some versions of the story: "Gartrell can't say with certainly whether the findings would apply to gay fathers. It's ''highly likely," she says."
Gartrell's study was limited to lesbian couples. On theoretical grounds, one could take her result as evidence not that homosexuals are good at child rearing but that women are, in which case it would imply the precise opposite of what she suggests. Insofar as the quote is evidence of anything, it is evidence of bias on the part of the researcher. As anyone familiar with statistical work knows, there are a lot of ways in which a researcher can tweak the design of a study, deliberately or not, to produce the result the researcher wants.
One way might be by the choice of the set of heterosexual couples to which the lesbian couples were being compared. The two groups might differ in important ways other than their sexual preferences. Most obviously, since the lesbian parents had conceived via artificial insemination, their pregnancies were all planned and all desired. If the comparison group contained a significant number of children from unplanned and unwanted pregnancies, that might explain why more of them had behavioral problems. One could imagine a variety of other possible explanations as well—and the news stories did not provide enough information to confirm or reject them.
Fortunately, nowadays, one is not limited to news stories. A web search quickly turned up the actual text of the article. Reading it, I discovered:
1. The two groups were not closely matched, due to data limitations, a problem that the authors noted. They differed strikingly in geographic location, since the lesbian couples were all recruited in the Boston, D.C., and San Francisco meteropolitan areas, while the data on children of heterosexual couples, coming from another researcher's work, was based on a wider distribution of locations. They were not matched racially—14% of the heterosexual couples were black, 3% of the lesbian couples were. They were not matched socio-economically—on average, the heterosexual couples were of higher SES than the lesbian couples.
The statistical analysis on which the story was based contained no controls for those differences, any one of which might have affected the conclusion. The authors could have compared the outcome of child rearing by white lesbian couples to the outcome of child rearing by white heterosexual couples, by high SES lesbian couples to high SES heterosexual couples, ... . They did none of that, although it is possible that in future work they will.
2. There was a second problem that had not occurred to me, possibly because I had not read the news story carefully enough. Questionaires went, at various points in the study, to both mothers and children. But the conclusion about how well adjusted the children were was based entirely on the reports of ther mothers. A more accurate, if less punchy, headline would have read: "Lesbian Mothers Think Better of Their Kids than Heterosexual Mothers Do."
My point in this post is not to criticize the authors of the study. There may have been good reasons why they used the data they did, despite its limitations, and they may be planning a more informative analysis of their results for later work. It is easy for an outside observer to suggest things scholars ought to have done, not always as easy for the scholars to follow the advice.
My point is rather about the information available to ordinary readers through newspapers, the webbed equivalent, radio and television, and similar sources. The implication of the news stories was that the study provided strong evidence that lesbian parents did, on average, a better job of child rearing than heterosexual parents. A reader who went to the trouble of locating and reading the published report of the study, as few would, would discover that that implication was false. The study provided some evidence for the conclusion, but not very much. It could as easily be interpreted as evidence that richer people do a worse job of child-rearing than poorer people, blacks worse than whites, parents from flyover country worse than the inhabitants of the coastal metropolises—or that lesbian parents are even more strongly biased in favor of their own children than other parents.
The only thing that the headlines provided clear evidence of was what their authors wanted their readers to believe.