There is no difference. The effects are due to the absence of a father in the home. The reason for that absence is irrelevant to the child.
That they are of the same gender is not relevant.
That's simply not true.
There's no magic in the number of "moms" in a child's life. It's the question of whether there are both mother and father, a male and a female parent, in a child's life that makes the difference. The research clearly indicates that, though you'd like to reinterpret the findings.
You can dream that the consequences of growing up fatherless are eliminated by simply adding a second "mom", but it's just not true.
I have no hatred toward gays and lesbians. But their choices have consequences attached to them, and many of those consequences are paid for by children.
This is inaccurate, home where the father is gone because of death do not have the same problems as homes in which the father is gone because the mom has multiple sequential boyfriends.