Lol did you read my post at all? All things being equal, we absolutely should not allow and certainly not "encourage" adoption by same-sex couples.
You don't see even one? How about that such a child be deprived of a mother or father?
Ay, ay, ay, George. We cannot intelligibly speak of which type of couple should be able to adopt or which one would be "better" if we don't speak with an assumption of balance, for doing so just lends itself to the producing forth of point-missing "well, shouldn't a same-sex couple be able to adopt if the alternative was that the child be raised by drug addicts?" nonsense.
Failed to give evidence of why? George, the answer is straightforward: decades of published research in psychology, social science, and medicine demonstrate that children do best when raised by a mother and father (especially the biological parents) in a long-term marriage (again, much of this research is referenced in David Popenoe, Life Without Father, Cambridge: Harvard University Press, 1996). Thats because a mother and a father each provide a unique and important contribution to their role as parents. Children who are raised for example in fatherless families suffer, on average, in every measure of well-being. They have higher levels of physical and mental illness, educational difficulties, poverty, substance abuse, criminal behavior, loneliness, and physical and sexual abuse (see Yale Medical Schools Dr. Kyle Pruett, Fatherneed: Why Father Care Is as Essential as Mother Care for Your Child (New York: Free Press, 2000), 17-34.).
Homosexual adoption, by design, will deny a child either a mother or father every time. By legalizing same-sex parenting, society declares by law that mothers and fathers are interchangeable. That means a mother offers no unique contribution to a child. A man could provide all the benefits of a woman.