Prof. Mark Regnerus shares his comments in National Review Online on the National Longitudinal Lesbian Family Study, which once again is garnering plenty of favorable press despite the methodological failings he points out:

"...What exactly is the NLLFS and why do I say it should be retired?

... the reason is that its sample — 78 kids growing up in activist households — is no longer a source for valid, reliable information. Why?

... The “Hawthorne effect” refers to the tendency of study participants to work harder or perform better because they know they are being studied. While it is typically applied to experimental research studies of worker productivity, the same could be true here. It’s a cousin to “social desirability bias,” which is closer to what I’m suggesting. In this case, I’m concerned that the kids feel pressure to give better-than-accurate portrayals of their household and personal life. When the adolescent children of lesbian parents are being intermittently interviewed for a study whose results have proven quite politically important — and almost always covered favorably by the mainstream media — it’s prudent for scholars to be skeptical about whether respondents are still offering valid and reliable responses years after they were first contacted. Some kids will always offer valid information, but given the fishbowl these 78 have lived in, I’m concerned that social desirability bias will affect disproportionate numbers of them, especially in contrast to far larger survey projects.

... I just don’t believe the 78 kids in the NLLFS are capable of reporting unbiased information any more, not after a childhood and adolescence spent entirely in a fishbowl. Even the NLLFS’s principal investigators suggested that 25 years of data collection may be enough. I would concur, and — since the study commenced in 1986 — we eclipsed that mark in 2011. Perhaps it’s time to commit significant funds — and a panoply of research perspectives — to a very large (and hence expensive), longitudinal, population-based data-collection effort that would make fans of the NLLFS and fans of the NFSS alike content with its methodology.

I’m all for more information. But if the data are to be valid and reliable, the study needs to be as free of source bias as is humanly possible. I won’t hold my breath, though, because in the case of lesbian parenting, a nationally representative sample is not what many of my scholarly, rational, and allegedly dispassionate colleagues in the social sciences appear to want."