Yeah... if you care about freezing sperm, you do NOT want to be on HRT. When I went on HRT, my ejaculate was already getting thinner by the end of week 1, it had changed completely from cloudy white to a transparent yellow liquid after about 3.5 weeks, and by the 6 month mark nothing at all was coming out anymore.
Seriously. Don't mess around with HRT at all if you want to freeze sperm. Get off HRT, wait few weeks for your body to recover, then freeze the sperm, then get back on it.