That's the title of NOM co-founder Maggie Gallagher's post in National Review on this topic:

Judge Vaughn Walker ruled in his decision overturning Proposition 8 that social science had disproven the idea that children benefit from being raised by their mom and dad in a marriage. The American Psychological Association has issued a proclamation to that effect, allegedly based on a neutral study of scientific evidence.

Today in the Social Science Journal, as Charles C. W. Cooke reports over on the home page, two new studies were published that challenge these assumptions and launch us into a new phase of the scientific debate.

Professor Mark Regnerus, the author of the New Family Structures Survey project, has published a study that is not only the largest and most comprehensive, it is only the second study based on a probability sample. Scientifically this is huge.

... On 25 of 40 outcome measures, adult children who reported their mother had a same-sex romantic relationship fared poorly compared to children raised by intact biological married parents. This should surprise no one. It doesn’t mean that gay parents are bad parents. Plenty of kids raised outside of intact married families do fine. Nonetheless, this new research tends to affirm that the ideal for a child is a married mom and dad.

Major family scholars such as Paul Amato, while cautioning that this should not be conclusive for policy questions such as same-sex marriage, affirm that this is an excellent study, indeed probably the best study we have to date on gay parenting.

... I’ll write more on this later. For access to the studies and to the “comments” by significant outside scholar, go here.