All of this smacks of the condemnation of the Copernican heliocentric solar system, which the Church promoted for years contrary to scientific evidence.  Gender identity as distinct from the biological determinism presupposed by traditional theology is a new understanding of the complexity of human sexuality.  While much is still unknown, there is an emerging consensus ( as with sexual orientation) that this is not something "chosen" by the individual but rather compelled by some deep seated compunction.  To respond to this condition with some authoritarian restatement of biological determinism is neither sensitive to those individuals affected nor particularly helpful in coming to deal with the reality of gender identity issues.  Continuing to insist that reality must be as it "should" be, based on some preconceived notions, rather than as it "IS" may comfort those longing for a smaller, purer group of true believers, but it hardly serves a Church in the world but not of it.