Feminizing hormone therapy may limit your fertility. If possible, it's best to make fertility decisions before starting treatment. The risk of permanent sterility increases with long-term use of hormones. This is particularly true for those who start hormone therapy before puberty begins. Even after stopping hormone therapy, the testicles may not recover enough to guarantee conception without infertility treatment.
If you want to have biological children, talk to your healthcare provider about the possibility of freezing sperm before starting feminizing hormone therapy. While gender-affirming hormone therapy usually improves mood, some people may experience mood changes or a worsening of anxiety, depression, or other mental health problems as a result of changes associated with the onset of a second puberty. The risk of blood clots, heart attacks, strokes, diabetes, and cancer as a result of hormone therapy is minimal, but it can be high, especially in people with co-existing health problems or who start hormone therapy after age 50. While some data suggests that stopping taking hormones for 3 to 6 months may cause your sperm count to return, it's best to assume that, within a few months of starting hormone therapy, you could permanently and irreversibly lose the ability to create sperm.
You should start feminizing hormone therapy only after talking to a health professional who specializes in caring for transgender people about the risks and benefits, as well as treatment alternatives. Progesterone is usually added to a regimen after hormone levels have stabilized after the initial period of initiation of estrogen and testosterone treatment. While it is possible to adjust medications and dosage to achieve certain specific goals, the way in which the body changes in response to hormones depends more on genetics and the age at which you start taking it, than on the specific dose, route, frequency, or types of medications taken. Starting hormone therapy at age 40, 50, or older may cause less dramatic changes than those seen at the beginning of the transition at a younger age, due to cumulative lifetime exposure to testosterone and decreased responsiveness to hormonal effects as the age of menopause approaches.
