...family studies scholar Loren Marks of Louisiana State University reviews the 59 studies that are referenced in the 2005 American Psychological Association brief that came to the conclusion that there are "no differences." Marks concludes that "not one of the 59 studies referenced ... compares a large, random, representative sample of lesbian or gay parents and their children with a large, random, representative sample of married parents and their children. The available data, which are drawn primarily from small convenience samples, are insufficient to support a strong generalizable claim either way." Marks's study casts significant doubt upon the older evidence on which the APA brief, and thus the "no differences" paradigm, rests.
... while critics of the NFSS have faulted it for lacking comparisons between children of IBFs and the children of committed and intact gay or lesbian couples, this was attempted, but was not feasible.
Although there is much speculation that today there are large numbers of same-sex couples in the U.S. who are providing a stable, long-term parenting relationship for their children, no studies based upon large, random samples of the U.S. population have been published that show this to be true, and the above-cited studies of different nations show that on average, same-sex couple relationships are more short-lived than those of opposite-sex couples.
The real difficulties lie in 1) small sample sizes of the studies most cited by the pro-homosexuality advocates 2) the lack of longitudinal studies where cause and effect may be better assessed and 3) comparing the past and present without being able to accurately gauge for the impacts of changing attitudes.
Even absent that academic data, I am confident in saying that faithful, monogamous, heterosexual, non-abusive (including no sexual contact with the children) parenting is best. For me, it's self-evident. Those who hope otherwise are engaging in nothing but wishful thinking. Their position will just never be vindicated by the whole truth.