Compassionate. Responsible. Fulfilling their oath to help first and avoid doing harm. - That's what I'd call a Doctor Who treats transsexuals.
There is no single medical specialty that covers all aspects of transsexual care. Medical sex changes involve multiple doctors.
Many of the doctors treating transsexual patients do not 'specialize' in trans patients. They started working on one medical issue they found important and then found that they could use the same skills to help transsexual patients. These doctors usually continue to practice their specialty on non-transsexual patients as well as transsexual patients.
A Doctor Who treats children is called a paediatrician
A doctor who treats the elderly (technically defined as any person over the age of 65) is a Geriatrician, or Gerontologist.
A doctor who treats animals is called a Veterinarian or a Veterinary Doctor
An oncologist treats people with cancer.
Doctor
An Opthalmologist.
That would be a pediatrician.
A doctor - or a podiatrist.
A Doctor who treats animal diseases and injuries is a veterinary surgeon (British English) - or Vet for short.
A psychiatrist
they are called either a therapist or a psyciatrist
neurologist specializing in memory disorders