Answer
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
1- A female therapist should treat people of the same gender. But rarely the female therapist has any say on that.
2- If the client is male and the female therapist has to engage in necessary physical contact, there is nothing wrong with that in order to help someone with their special needs.
Sheikh Omar Suleiman answers your question in the following video:
Almighty Allah knows best.
For more, see these fatwas:
Having Pubic Hair Removed with Laser by a Female Doctor: OK?
Can Circumcision Be Performed By a Non-Muslim Doctor?
Can a Female Dentist Treat Male Patients?
Source: www.faithiq.org