I believe that homosexuality is a behavior that is learned and changeable, instead of inborn.
Setting aside whether this is true, why does this matter? How does it have the least bit of relevance?
Something that is without a doubt best for children are a mom and a dad.
Plenty of reason to doubt this. For instance, "child abuse".
But aside from that, what relevance is that? Do you think that banning gay marriage will cause a child to live in two-parent male/female households? I suspect that, absent another rule that is completely separate from gay marriage, you'll get exactly as many pairs of gay parents whether or not they are married.
If you don't think this makes a difference look at all the statistics - from physical, physiological and mental health and including the heightened probabilities of drug use, suicide, school drop out rates, wedlock births and crime - if you just take the father out of the equation
Do you have any statistics that compare to female parents to a male and female parent? Because comparing a male and female parent, to a single female parent, is not isolating sexual diversity as what improves parenting. The number of parents is clearly relevant.
...you are opposed to wedlock births????
Having two women trying to raise a child mimics correctly the absence of a father
No. Come on. That's obviously BS. It's pretty obvious why two parents would be better than one.
So I decided to look up the statistics on this, since you mentioned that they existed, and what I found completely contradicts you. It shows that *only* the number of parents really matter, and their gender is irrelevant: http://onlinelibrary.wiley.com...
It may even be that three live-in parents are better than two, but it's much harder to find statistics on that.
If this is really your reasoning, you should push for laws that remove children from single-parent and same-sex-parent households, and redistribute them in mixed-sex households (perhaps some polyamorous households, maybe some non-romantically-involved roommates?). Gay marriage doesn't matter to you, it's single-sex parenting, and you don't really help that by opposing gay marriage.