I really shouldn't care otherwise so long as the soldier has the necessary combination among physique, muscle, fitness, athleticism, marksmanship, aptitude, discipline, and temerity for the particular job responsibility to sacrifice his life in practice and war.  Not everybody can be "heroes," not even those that insist that they want to be.  Why should anything else matter...so long as military morale and esprit de corps doesn't degrade and we taxpayers don't have to pay for the human desire to change one's gender and the consequences from doing  or having done so?