"People who have gender dysphoria feel strongly that they are not the gender they physically appear to be.
For example, a person who has a penis and all other physical traits of a male might feel instead that he is actually a female. That person would have an intense desire to have a female body and to be accepted by others as a female. Or, someone with the physical characteristics of a female would feel her true identity is male.
Feeling that your body does not reflect your true gender can cause severe distress, anxiety, and depression. "Dysphoria" is a feeling of dissatisfaction, anxiety , and restlessness. With gender dysphoria, the discomfort with your male or female body can be so intense that it can interfere with the way you function in normal life, for instance at school or work or during social activities.
Gender dysphoria used to be called “gender identity disorder.” But the mismatch between body and internal sense of gender is not a mental illness. Instead, what need to be addressed are the stress, anxiety, and depression that go along with it."
Gender Dysphoria: What It Is and How It's Treated. (n.d.). Retrieved February 13, 2016, from http://www.webmd.com/mental-health/gender-dysphoria