PZ has an excellent post up, which I hope you’ve seen already, regarding the hatred of the Catholic bishops. I want to call out a small piece of that larger statement here:
Children especially are harmed when they are told that they can “change” their sex or, further, given hormones that will affect their development and possibly render them infertile as adults.
If you read this as the bishops obviously intend you to read it, this portion of their statement says:
You can’t actually change your sex, so telling this to children is bad. Also, it’s even worse when you change the sex of another human being, particularly a child.