I'd be willing to wager they are a same sex couple themselves who adopted this kid for just this kind of action.
I'm thinking along the same lines.
If a female he/she “identifies” as a male marries a male he/she who “identifies” as a female would a male child have a mother who identifies as a father and a father who identifies as a mother? Then if the kid is a he/she is it the son who identifies as a daughter of the mother who identifies as a father. And... they have a female kid who blah blah blah
So when there is a father daughter event at school, who goes?