What IsYour thoughts on transgender people?

 Transgender meaning that their gender (what they perceive themselves as) does not match what sex they are (what's in between their legs).
What are your thoughts on people with this gender-sex dissonance?
Are they normal people?
Do they have the right to question themselves?
Would you ever date one?
What would you do if you found out your partner was one after the fact?
What if one of your friends turned out being transgender?