The only problem? There is no data to support the conclusions of the study, which was done by a right-wing sociologist who, among other things, defined a queer parent as anyone who had a same sex relationship (of any duration) while a child was growing up.
Fortunately the problems with the study are being widely identified. See for example this Huffington Post article: http://www.huffingtonpost.com/zinnia-jones/regnerus-same-sex-parents-study_b_1595213.html
Other, credible research finds that the children of a two parent lesbian household are as well-adjusted on all indicators of psychological health; and actually are more open-minded and tolerant that children raised in two parent heterosexual household.