Thus, they are less likely to confound the effects of having a sexual minority parent with the consequences of divorce.
The widespread pattern of children being raised from infancy in two-parent gay or lesbian homes is relatively recent.
Studies of LGBT parenting have sometimes suffered from small and/or non-random samples and inability to implement all possible controls, due to the small LGBT parenting population and to cultural and social obstacles to identifying as an LGBT parent.
Most research to date has been conducted on white lesbian mothers who are comparatively educated, mature, and reside in relatively progressive urban centers, most often in California or the Northeastern states." The overall methodological sophistication and quality of studies in this domain have increased over the years, as would be expected for any new area of empirical inquiry.
More recent research has reported data from probability and community-based convenience samples, has used more rigorous assessment techniques, and has been published in highly respected and widely cited developmental psychology journals, including Child Development and Developmental Psychology.
Data are increasingly available from prospective studies.
In addition, whereas early study samples consisted mainly of children originally born into heterosexual relationships that subsequently dissolved when one parent came out as gay or lesbian, recent samples are more likely to include children conceived within a same-sex relationship or adopted in infancy by a same-sex couple.
A 1993 review published in the Journal of Divorce & Remarriage identified fourteen studies addressing the effects of LGBT parenting on children.
The review concluded that all of the studies lacked external validity and that therefore: "The conclusion that there are no significant differences in children reared by lesbian mothers versus heterosexual mothers is not supported by the published research data base." Many of these studies suffer from similar limitations and weaknesses, with the main obstacle being the difficulty in acquiring representative, random samples on a virtually invisible population.
The studies specific to same-sex parenting were published in leading journals in the field of child and adolescent development, such as Child Development, published by the Society for Research in Child Development, Developmental Psychology, published by the American Psychological Association, and The Journal of Child Psychology and Psychiatry, the flagship peer-review journals in the field of child development.