Gays CAN reproduce, they're not sterile by default. Straight childless couples CAN'T reproduce, but we're still humans. As there are millions of children in orphanages around the world (some of which are right now held hostages by Russia, to make sure they don't end up in countries where gays have human rights), the problem is not too few kids, but too few good parents.
As a human offspring is incredibly helpless and vulnerable during its first four years or so, Nature intended there to be other people than just the parents around the offspring, to help take care of it, and to take over completely if something happened to one or both of the parents, in order to make sure that the offspring survived into adulthood.
It's not a question of preferment, but being born that way, asshole! Would YOU choose to be something that would make you hated and vilified by evil people like you, possibly even beaten up or murdered by those people, or subjected to "corrective rape". Doesn't it sound just marvelous?
How is Christianity in accordance with nature?
Foster children and orphans should be given to loving, caring parents, regardless of gender. Growing up with two loving fathers must be infinitely better than growing up in an overcrowded orphanage, whatever you think about homosexuality, surely.
If the "real parents" were not able or willing to take care of the child properly, then they are not really real parents. Parents have no inalienable right to their children, but children have the right to have parents who actually take care of all their needs, physically, psychologically and socially.