No, it goes beyond sexual orientation in plain terms and it is certainly NOT, as you say, a matter of being deluded by antiquated preconceptions of LGBTQ people. What it IS a matter of is that the different roles of a father and mother bring unique perspectives into a child's life that allow him or her to both receive love and get a well-rounded experience while growing up. Don't get me wrong - there are a sizable amount of straight couples that are unfit to be parents, and adoption agencies should take this into consideration. But I feel that each individual child at least deserves to personally find out what a qualified (as in able to provide for the child's needs) man and woman can offer them while being raised. And the child arriving at their personal sexual preference should be an entirely separate matter away from this.
@Ars-Gratia-Artis3mos3MO
"And the child arriving at their personal sexual preference should be an entirely separate matter away from this."
It should be and I agree. And from my personal experience, there are two types of gay/bi people: "Normal" ones who just live their lives like a normal person, don't try to get people to switch sides, and don't go around lobbying for equality and crap because that nonsense is over now (I lean more this way) and the annoying ones (granted, more tq+ hit this but) who constantly denigrate straight people, get really dramatic, and try to force their beliefs on their kids. Let the kid develop himself, don't try to push them. If they're gay, they'll figure it out pal.
