What are you planning to do to become more sure? Might you consider withholding judgement until such time as you become more sure?
I plan on doing nothing to become more sure, other than the usual general gathering of information that is part of my life. I do not consider rendering an opinion on a discussion board 'judgement'. My opinions have no bearing of any kind on the progression of whether or not gays are allowed to marry (which I already support), or adopt (which I support, but with the reservation that hetero couples should be prefered), nor are they likely to in the near future. Should they ever be relevant then, yes, I would thoroughly research the issue.
My opinion is based on what I know about child development, most of which comes from following a Introduction to Psychology course at university. Children from single parent families generally do less well than parents from two parent families and exhibit more behavioural problems. They do this even if the child is raised in the home of the mother, and effectively raised by the mother's mother, the mother and, in some cases, extended family. However, research in America has found that by introducing strong male role models into the social and school lives of children raised by single parents in deprived areas of Los Angeles it is possible to significantly reduce these problems.
I therefor conclude that children, probably, require both male and female parent figures in their lives in order to have the best possible development. Would you agree this is a reasonable conclusion from that evidence?