Name changed for this because it's such a delicate subject and I'm probably a bit on the conservative side.
Honestly I think the ideal situation is a loving and involved biological mother and father. But I acknowledge that "loving and involved" is not always the case when children are made the 'usual' way, either because the parents are together but one or both are unloving/uninvolved or because there is one absent parent somewhere down the line.
However, I'm slightly on the fence about whether it's fair or a particularly good idea to deliberately engineer a less than ideal situation re an absent father, whether that's single parenthood or same same sex couples, even when the mother is biologically related to and carries the child. Probably not, but then there are so many feckless fathers in "normal" circumstances I question whether the odds of an ideal circumstance in the traditional set up are compelling enough to properly take against that particular alternative given the primary bond is maintained.
I absolutely do not support surrogacy - for gay men, heterosexual couples or lesbians. Anyone. Because it involves the deliberate breaking of the maternal bond at birth in order to serve the desires of adults. I think it's unutterably selfish to knowingly and deliberately inflict that on a newborn for your own purposes.
Adoption is different because it's making the best of a less than ideal circumstance that has arisen through circumstance rather than being orchestrated for the benefit of adults. Re who adopts, I'm open to research re what works best for the children (which i think should be the only criterion) but if it's a choice between the care system and any loving substitute parent (single, couple, gay, straight, male, female) I would expect the latter to be better for the child every time.
Oh and I think that every child, in every circumstance, should have an absolute right to know who their biological parents are.
So I suppose i think it's always weighing a situation up against the alternatives to make a judgement. I think that the only criterion should be what is optimal for the child - adult feelings and wants and equality and 'fairness' should count for exactly nothing when considering child welfare.
I've thought this through as I've typed so fully expect that there are things I haven't thought of, but those are my immediate two cents! Interesting question, OP.