A: Only if she wants to, but if so indeed she can, without difficulty, by getting the right form of hormone therapy.  On the other hand one sub-group of trans women have quite the opposite problem, that of having too much sexuality, far more than they want & for them it is an easy matter to to tone down this excessive, obsessional over-drive also, if that is their desire.  (See explanatory  article on this site under 'Featured Articles')