The proper control is not the non-transgendered population, but the transgendered who did not get re-assignment surgery.
If the non-surgery transgender group has a suicide rate 50x the population at large, then the surgery would be pretty successful in psychological terms.
If it had a suicide rate 10x the population, no, not so much.
Exactly.
There is another important point regarding causality/correlation when it is brought up by advocates of sex-change surgery. If they argue that the suicides are related to pre-existing mental illness or distress, then they are admitting that those who choose surgery are either mentally ill or under mental duress.
This contradicts their contention that gender identity disorder isn't disordered.
I suppose they'd answer that this mental distress is caused by cultural rejection. But even granting that premise, surgery results in such a high risk of post-op suicide that social rejection is preferable.
In actuality, these people don't face public ridicule. Jenner is being widely hailed.