1.1. Sampling concerns in previous surveys
Concern has arisen, however, about the methodological quality of many studies focusing on same-sex parents. In particular, most are based on non-random, non-representative data often employing small samples that do not allow for generalization to the larger population of gay and lesbian families (, and ). For instance, many published studies on the children of same-sex parents collect data from “snowball” or convenience samples (e.g., , , , and ). One notable example of this is the National Longitudinal Lesbian Family Study, analyses of which were prominently featured in the media in 2011 (e.g., ). The NLLFS employs a convenience sample, recruited entirely by self-selection from announcements posted “at lesbian events, in women’s bookstores, and in lesbian newspapers” in
and . While I do not wish to downplay the significance of
such a longitudinal study—it is itself quite a feat—this sampling approach is a
problem when the goal (or in this case, the practical result and conventional
use of its findings) is to generalize to a population. All such samples are
biased, often in unknown ways. As a formal sampling method, “snowball sampling
is known to have some serious problems,” one expert asserts (, p. 59). Indeed, such samples are likely biased
toward “inclusion of those who have many interrelationships with, or are
coupled to, a large number of other individuals” (, p. 531). But apart from the knowledge of
individuals’ inclusion probability, unbiased estimation is not possible. San Francisco
Further, as entreated, consider the convenience sample recruited from within organizations devoted to seeking rights for gays and lesbians, like the NLLFS sampling strategy. Suppose, for example, that the respondents have higher levels of education than comparable lesbians who do not frequent such events or bookstores, or who live elsewhere. If such a sample is used for research purposes, then anything that is correlated with educational attainment—like better health, more deliberative parenting, and greater access to social capital and educational opportunities for children—will be biased. Any claims about a population based on a group that does not represent it will be distorted, since its sample of lesbian parents is less diverse (given what is known about it) than a representative sample would reveal ().
To compound the problem, results from nonprobability samples—from which meaningful statistics cannot be generated—are regularly compared with population-level samples of heterosexual parents, which no doubt are comprised of a blend of higher and lower quality parents. For example, and inquired about the sexual orientation and behavior of adolescents by comparing data from the National Survey of Family Growth (NSFG) with those in the snowball sample of youth in the NLLFS. Comparing a population-based sample (the NSFG) to a select sample of youth from same-sex parents does not provide the statistical confidence demanded of good social science. Until now, this has been a primary way in which scholars have collected and evaluated data on same-sex parents. This is not to suggest that snowball samples are problematic as data-collection techniques, only that they are not adequate for making useful comparisons with samples that are entirely different with regard to selection characteristics. Snowball and various other types of convenience sampling are simply not widely generalizable or comparable to the population of interest as a whole. While researchers themselves commonly note this important limitation, it is often entirely lost in the translation and transmission of findings by the media to the public.
1.2. Are there notable differences?
The “no differences” paradigm suggests that children from same-sex families display no notable disadvantages when compared to children from other family forms. This suggestion has increasingly come to include even comparisons with intact biological, two-parent families, the form most associated with stability and developmental benefits for children ( and ).
Answering questions about notable between-group differences has nevertheless typically depended on with whom comparisons are being made, what outcomes the researchers explored, and whether the outcomes evaluated are considered substantial or superficial, or portents of future risk. Some outcomes—like sexual behavior, gender roles, and democratic parenting, for example—have come to be valued differently in American society over time.
For the sake of brevity—and to give ample space here to describing the NFSS—I will avoid spending too much time describing previous studies, many of whose methodological challenges are addressed by the NFSS. Several review articles, and at least one book, have sought to provide a more thorough assessment of the literature (, , , and ). Suffice it to say that versions of the phrase “no differences” have been employed in a wide variety of studies, reports, depositions, books, and articles since 2000 (e.g., , , , , , , and ).
Much early research on gay parents typically compared the child development outcomes of divorced lesbian mothers with those of divorced heterosexual mothers (). This was also the strategy employed by psychologist Fiona , who compared lesbian mothers with single, divorced heterosexual mothers and found “no systematic differences between the quality of family relationships” therein. , using 44 cases in the nationally-representative Add Health data, reported that teenagers living with female same-sex parents displayed comparable self-esteem, psychological adjustment, academic achievement, delinquency, substance use, and family relationship quality to 44 demographically “matched” cases of adolescents with opposite-sex parents, suggesting that here too the comparisons were not likely made with respondents from stable, biologically-intact, married families.
However, small sample sizes can contribute to “no differences” conclusions. It is not surprising that statistically-significant differences would emerge in studies employing as few as 18 or 33 or 44 cases of respondents with same-sex parents, respectively ( , and ). Even analyzing matched samples, as a variety of studies have done, fails to mitigate the challenge of locating statistically-significant differences when the sample size is small. This is a concern in all of social science, but one that is doubly important when there may be motivation to confirm the null hypothesis (that is, that there are in fact no statistically-significant differences between groups). Therefore, one important issue in such studies is the simple matter of if there is enough statistical power to detect meaningful differences should they exist. is the first scholar to employ a large, random sample of the population in order to compare outcomes among children of same-sex parents with those of heterosexual married parents. He concluded—after controlling for parents’ education and income and electing to limit the sample to households exhibiting at least 5 years of co-residential stability—that there were no statistically-significant differences between the two groups in a pair of measures assessing children’s progress through primary school.
Sex-related outcomes have more consistently revealed distinctions, although the tone of concern about them has diminished over time. For example, while the daughters of lesbian mothers are now widely understood to be more apt to explore same-sex sexual identity and behavior, concern about this finding has faded as scholars and the general public have become more accepting of GLB identities (). noted that girls raised by lesbian mothers reported a higher number of sexual partners in young adulthood than daughters of heterosexual mothers. Boys with lesbian mothers, on the other hand, appear to display the opposite trend—fewer partners than the sons of heterosexual mothers.
More recently, however, the tone about “no differences” has shifted some toward the assertion of differences, and that same-sex parents appear to be competent than heterosexual parents ( and ). Even their romantic relationships may be better: a comparative study of
gay civil unions and heterosexual marriages revealed that same-sex couples
report higher relationship quality, compatibility, and intimacy, and less
conflict than did married heterosexual couples (). review article on gender and
parenting asserts that, Vermont
based strictly on the published science, one could argue that two women parent better on average than a woman and a man, or at least than a woman and man with a traditional division of labor. Lesbian coparents seem to outperform comparable married heterosexual, biological parents on several measures, even while being denied the substantial privileges of marriage (p. 17).
Even here, however, the authors note that lesbian parents face a “somewhat greater risk of splitting up,” due, they suggest, to their “asymmetrical biological and legal statuses and their high standards of equality” (2010, p. 17).
Another meta-analysis asserts that non-heterosexual parents, on average, enjoy significantly better relationships with their children than do heterosexual parents, together with no differences in the domains of cognitive development, psychological adjustment, gender identity, and sexual partner preference ().
However, the meta-analysis reinforces the profound importance of is doing the reporting—nearly always volunteers for small studies on a group whose claims about documentable parenting successes are very relevant in recent legislative and judicial debates over rights and legal statuses. suggests caution:
Parental self-report, of course, may be biased. It is plausible to argue that, in a prejudiced social climate, lesbian and gay parents may have more at stake in presenting a positive picture….Future studies need to consider using additional sophisticated measures to rule out potential biases…
Suffice it to say that the pace at which the overall academic discourse surrounding gay and lesbian parents’ comparative competence has shifted—from slightly-less adept to virtually identical to more adept—is notable, and rapid. By comparison, studies of adoption—a common method by which many same-sex couples (but more heterosexual ones) become parents—have repeatedly and consistently revealed important and wide-ranging differences, on average, between adopted children and biological ones. In fact, these differences have been so pervasive and consistent that adoption experts now emphasize that “acknowledgement of difference” is critical for both parents and clinicians when working with adopted children and teens (). This ought to give social scientists studying gay parenting outcomes pause, especially in light of concerns noted above about small sample sizes and the absence of a comparable recent, documented improvement in outcomes from youth in adopted families and stepfamilies.
Far more, too, is known about the children of lesbian mothers than about those of gay fathers (, and ). note that while gay-male families remain understudied, “their daunting routes to parenthood seem likely to select more for strengths than limitations.” Others are not so optimistic. One veteran of a study of the daughters of gay fathers warns scholars to avoid overlooking the family dynamics of “emergent” gay parents, who likely outnumber planned ones: “Children born into heterosexually organized marriages where fathers come out as gay or bisexual also face having to deal with maternal bitterness, marital conflict, possible divorce, custody issues, and father’s absence” (, p. 291).
Regardless of sampling strategy, scholars also know much less about the lives of children of gay and lesbian parents, or how their experiences and accomplishments as adults compare with others who experienced different sorts of household arrangements during their youth. Most contemporary studies of gay parenting processes have focused on the present—what is going on inside the household when children are still under parental care ( , and ). Moreover, such research tends to emphasize outcomes like parental divisions of labor, parent–child closeness, daily interaction patterns, gender roles, and disciplinary habits. While such information is important to learn, it means we know far more about the experience of in households with children than we do about young adults who have already moved through their childhood and now speak for themselves. Studies on family structure, however, serve scholars and family practitioners best when they span into adulthood. Do the children of gay and lesbian parents look comparable to those of their heterosexual counterparts? The NFSS is poised to address this question about the lives of young adults between the ages of 18 and 39, but not about children or adolescents. While the NFSS is not the answer to all of this domain’s methodological challenges, it is a notable contribution in important ways.