This is the latest edition of the U.S. National Longitudinal Lesbian Family Study. We are still waiting for anyone to criticize this study for not using a random sample, or for saying stability doesn't matter to children (see Pediatrics 2010, Gartrell).
In this latest edition they are reporting that children raised by two lesbian moms do not do better if they report having a "male role model":
"...About half of the young people in the study, both boys and girls, report having a significant male role model in their life, even though they have two mothers. But there was no difference in psychological well-being between those who have such a role model and those who do not. There was also no evidence that the presence of a male role model affects traits commonly associated with gender roles or that boys require a male role model to be well-adjusted.
Previous research based on this study has found no difference in well-being between children raised in lesbian families and and those in heterosexual two-parent families. The study is confined to planned lesbian families, meaning that both partners identified as lesbian before having children. Researchers recruited participants between 1986 and 1992 and have checked in with them at various points in their lives. Most of the participants are middle-class." -- The Advocate