This month yielded yet another published study — which received positive media attention — based on the National Longitudinal Lesbian Family Study. The NLLFS is about to enter its third decade of following the same 78 respondents, who were “planned” and born to lesbian mothers employing artificial reproductive technology; in nearly all the families studied, the children were being raised by their biological mother and her partner. While any sociologist worth his or her degree can appreciate the laborious task of keeping track of and reinterviewing the same group of people over many years, this particular data-collection effort probably ought to be retired. And yet it continues to appear in peer-reviewed journal articles in the health and social sciences. What exactly is the NLLFS and why do I say it should be retired?
First, let me say that my skepticism about the NLLFS — shared by plenty of social scientists who wouldn’t go on record with their misgivings in the present chilling scholarly climate — is not at all due to the researchers who oversee the project, the authors who make use of it, or even the politically motivated funders who underwrite it. We all have our perspectives and interests, and the academy is big enough for all of us. (I hope.)
No, my misgivings are due to the great likelihood that the data sources — the respondents themselves — have been increasingly compromised, placing the very validity and reliability of the data in question. How so?
The NLLFS employs a convenience sample, recruited entirely from announcements posted “at lesbian events, in women’s bookstores, and in lesbian newspapers” in Boston, San Francisco, and Washington, D.C. As the late family sociologist Steven Nock warned, the level of sample bias such an approach introduces is significant. The lesbian parents whose children are being studied are whiter (94 percent), more educated (67 percent college graduates), of higher socioeconomic status (82 percent held professional or managerial positions), and more politically motivated than lesbians who do not frequent such “events” or bookstores, or who live in cities like San Antonio or Kansas City, or in smaller towns across the country. (Aren’t they important, too?) Anything that is correlated with educational attainment, for example — better health, more deliberative parenting, greater access to social capital and educational opportunities for children — will be biased in analyses. Any claims about a population (in this case, American lesbian parents) based on a subgroup that does not represent the whole will be distorted, since its sample is far less diverse (given what we know about it) than a representative sample would be. Indeed, there’s nothing “national” about the NLLFS.
I have no objection at all to the collection of snowball-sample data, only to its popular use as a source of information about all children of lesbian parents. If the NLLFS were simply used to understand the world of lesbian parents and their children among the elites in those three cities, then that would be just fine. But it’s not. In this case, the practical result and conventional use of its findings — and that is key — is to generalize to the population of lesbian parents across America. While researchers themselves commonly note this limitation, it is entirely lost in the translation and transmission of findings by the media to the public.
So for nearly 20 years the scholarly community has been treated to studies of this unique small cluster of kids, and the general public has been left with the impression that they represent the whole population of children of American lesbian mothers. They do not. The NLLFS’s sample doesn’t even share the population characteristics of same-sex-couple households that its sponsor — the Williams Institute of UCLA — describes in its own publication. In social reality — the one described in the U.S. Census — such households are less well-off economically, less white, and with less-educated parents than the households in the NLLFS. Everything about the NLLFS suggests a sample of highly privileged children being raised by parents with significant resources living in communities that offer notable social support.
In other words, it’s not the Census (or even the NFSS, the New Family Structures Study, with which I am affiliated) that needs to explain the diversity of lesbian motherhood that really exists in America. They’ve already done so. It’s the NLLFS that ought to explain its utter lack of diversity. It is from this select group of kids, not from the Williams Institute’s population-based estimates, that the media get their information about how the children of lesbian households are faring.
And yet all this is not actually why I think it’s time for the NLLFS to shutter its operation. No, the reason is that its sample — 78 kids growing up in activist households — is no longer a source for valid, reliable information. Why?