I’m sure this revelation must have been a huge shock to you and your whole family. I have worked with several transgender and transsexual clients over the years and I can assure you that Gender Identity Disorder is a real condition. It is a medical condition which also has many psychological, emotional and social ramifications.
Transsexuals can be male-to-female (MtF) or female-to-male (FtM). Your brother is a male-to-female transsexual and his goal is to make his outside physical appearance, body, and social gender presentation match his inside feelings of being “a woman in the wrong body”. He has probably been holding this secret for many years, possibly decades.
Most transsexual people have been trying to deal with this on their own or with help from medical and counseling professionals for a very long time before telling the family. By the time they tell their family, they are quite sure that they truly have this condition and that they absolutely need to transition. Most are terrified of disclosing this to family and wonder if their family members can deal with this major change.
The World Professional Association for Transgender Health (WPATH) is a group of professionals and people affected by the disorder who have put together official “Standards of Care” that guide physicians, surgeons and mental health professional in providing services to transgender individuals and their families. Therapists who are also Gender Specialists follow these Standards of Care so that no one who is not truly suffering from Gender Identity Disorder is inappropriately given hormone therapy or surgery.
I’m sure your brother was scared and nervous to share this with you. Many transgender people are rejected by their families but many are not. Everyone I have ever worked with wants to be accepted and loved by their family. Don’t be afraid to ask him questions and follow up with suggested books and web sites that explain this condition to family members and friends. This is the beginning of a big adjustment for you and your family, but inside, this is the same sibling you have always known, just in a very different packaging. As a result of this transition, she will be more true to herself and that will almost certainly make her a much happier person.