Lesbian Parenting and Media Bias

David Friedman, son of Nobel prize winner Milton Friedman, offers his thoughts on the "Lesbian Parenting Study".

A recent and widely reported news story, headlined "Kids of lesbians have fewer behavioral problems, study suggests," reported that "A nearly 25-year study concluded that children raised in lesbian households were psychologically well-adjusted and had fewer behavioral problems than their peers."

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.

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.

....

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 their 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.

The only thing that headlines provided clear evidence of was what their authors wanted their readers to believe.