The Unnatural Race

Something I've been encountering a lot recently with other people is the topic of gay adoption. (Could it be from the recent election wherein the various electorates voted against children in the system?)

Something rather baffling is how the point of homosexuality not being natural comes up. When this argument comes up in homosexuality discussions, my first thought to myself is why, by any logic, should laws be based on what's natural?

In gay adoption discussions, though, this line of argument is especially puzzling. What of the latter half of the phrase: adoption? I recently had a conversation with a Christian friend of mine along the following lines:

Me: Why are you opposed to gay adoption? As an adopted child, I would think you, of anyone, would support it.
Him: I do support adoption, just not gay adoption.
Me: Why not gay adoption? What's the difference between adoption by heterosexual or homosexual parent(s)? The result in both cases is an adoption. Shouldn't that be our objective?
Him: Homosexuality is unnatural, though.
Me: Why should that be a criterion?
Him: It's unhealthy for a child to grow up in that unnatural relationship.
Me: You're adopted, though, right? Adoption is unnatural too, and you're not against that.
Him: How do you figure?
Me: The natural order of things is that you have a child and then rear the child. It is unnatural to rear another's offspring. You just said that it's unhealthy for a child to grow up in an unnatural relationship; an parent-adopted child is an unnatural relationship.
Him: It's not unnatural, though. There are plenty examples of it in the animal kingdom of some dog taking care of a kitten or something.
Me: There's also plenty of examples of homosexuality in the animal kingdom, too, though.

It went on from there with him continuing to refute me using common refutations of the "homosexuality is unnatural."

After I began reading and thinking more, I have never understood the "nature" argument as any sort of defense of a law. There are plenty of natural things we prohibit. For example, defecation in the outdoors is very natural; however, we have chosen to prohibit people from defecating in public for good reasons (mainly sanitation).

There are also many (many) unnatural things we do not prohibit and, in fact, advocate. Blood donation, for example, is very unnatural. A needle is inserted into your arm, your blood is withdrawn and deposited in a bag, that bag is processed and stored, and then that blood is put into someone else's body.

There is a good reason we have chosen not to prohibit blood donation: the recipients need the blood. I could not fathom opposing blood donation under the banner of "it is unnatural." In the end, shouldn't we recognize the parallel to gay adoption? We should choose not to prohibit gay adoption for the same reason: the recipients need the adoption. How can people march under the banner of "it is unnatural" when there are so many children in need? Someone should contact Arkansas and find out. (Oh wait, the ACLU already has.)