I am not sure I understand the question. All I care about for both soldiers, astronauts, etc. is whether they are physically fit and able to do the job.
nice dodge, mental health is irelevant? When I stretch it - i have same problem with new ''Alien' movies. I just can't stand that fact that you would pick so volatile and ''disturbed'' people on mission costing bazilions of cash. If it would be on you wouldn't you pick people 'suited' for that job? I think military is very similiar in that regard...
I wasn't trying to dodge, I really didn't understand your question. So your feeling is that transgender people are not mentally equipped to handle military service, I take it? That seems like a pretty serious accusation, and also a slippery slope.
Are women unfit for duty? Hormones and all that.
There already is a mental health requirement for enlistees in the military. The only thing that should matter is if the person can pass that, regardless of anything else. Lets be honest, the military is going to attract some head cases. Their gender identity is pretty low on my list of worries as to who we give access to heavy weaponry.
What I am trying to say is that you probably want to minimalize risks and costs associated with it. And yes, I do think that transgender people are not the most mentally stable persons. I think its quite common knowledge that they have to take quite a lot of drugs and go to psychologists.