You create a false dichotomy.
We can teach biology. Sexuality falls into morality, and that falls under The Truth And Meaning of Human Sexuality.
You again create a false dichotomy. Your premise is flawed.
What we can teach is the Truth. We cannot teach falsities in the name of some sort of utilitarian ethic. That would be a lie.
We, as Catholics, can only proclaim the Truth. We cannot *support *or *advocate *anything other than the Truth. Therefore, we cannot **support **the teaching of lies in the public schools or anywhere else. We must *advocate *for the teaching of the Truth or of nothing contrary to it. And, we must protect children from these false ideas to the best of our ability should the schools choose to disregard our advocacy of that which is True.
Again, see The Truth And Meaning Of Human Sexuality for the Church’s teaching. The parents are the primary educators of their children on this topic. The State cannot replace them, and we cannot advocate, support, or condone any attempts to do so.