A book I'm reading lays out the criteria for an ideal gender therapist, as:
1) A licensed or certified mental health professional
2) with a knowledge base in human development, human sexuality, and/or transgender mental health care,
3) experience in treating anxiety, depression, and PTSD,
4) an open mind about the diversity of gender experience,
5) comfort with "cross dressing" and other forms of gender expression,
6) a willingness to learn more about the transition process, and seek supervision or consultation with a Senior Gender Specialist if necessary,
7) a collaborative approach to treatment planning,
8) a willingness to consult with and educate family members, schools, or employers if the need arises,
9) experience writing letters of referral, and
10) access to information about endocrinologists, surgeons, and other professionals and services as needed.
Hope this helps.