A major concern with hormone therapy is potential loss of fertility. Oestrogen and testosterone therapy can cause shrinkage of the testicles and ovaries, and this may not reverse when hormone therapy is ceased. Having said this many people take a break from hormone therapy and are able to conceive. It is likely that the longer you take hormone therapy, the more likely your fertility will be impaired in the longer term.
It is important to consider your future fertility prior to commencing hormone therapy. Talk to your GP about your options, which may include referrals for sperm banking or egg freezing.