Transgender are people that were born as one sex but transitioned to the other sex at some point in their life. They identify with genders opposite to the one they were born. They are also known as transvestites and there is a lot of controversy associated with them. These people think that they have the soul of the opposite gender and that they are in the wrong body.
Many of these people take hormones to transit and then ultimately have a gender reassignment surgery to change their genitals. Many transgender are not recognizable as their earlier self. The awareness is spreading which is helping people open up to the concept, but there is still a long way to go.
Transgender people identify themselves with the sex opposite to the one they were born with. This is different from cross-dressers i.e transvestites, and from drag artists, for these are people of one gender deliberately dressing and acting as the other, sometimes for entertainment, sometimes for the experience of being in another body.
Transgender folk feel they are always in the wrong body and that they should have been born in the gender they identify with. Increasingly, help including medical help, is provided to such individuals although the procedures and acts involved in physically changing gender may be very disturbing if not painful. Nowadays, there is more understanding and tolerance even in primary school for children who do not feel right in the body they were born with.