Biological sex is assigned at birth, depending on the appearance of the genitals. Gender identity is the gender that a person "identifies" with or feels themselves to be.
While biological sex and gender identity are the same for most people, this is not the case for everyone. For example, some people may have the anatomy of a man, but identify themselves as a woman, while others may not feel they are definitively either male or female.
This mismatch between sex and gender identity can lead to distressing and uncomfortable feelings that are called gender dysphoria. Gender dysphoria is a recognised medical condition, for which treatment is sometimes appropriate. It is not a mental illness.
The condition is also sometimes known as gender identity disorder (GID), gender incongruence or transgenderism.
Some people with gender dysphoria have a strong and persistent desire to live according to their gender identity, rather than their biological sex. These people are sometimes called transsexual or trans people. Some trans people have treatment to make their physical appearance more consistent with their gender identity.
Gender dysphoria is not the same as transvestism or cross-dressing and is not related to sexual orientation. People with the condition may identify as straight, gay, lesbian, bisexual or asexual, and this may change with treatment.
What causes gender dysphoria?
The exact cause of gender dysphoria is unclear.
It was traditionally thought to be a psychiatric condition, with its causes believed to originate in the mind.
However, more recent research suggests the condition may actually be the result of the abnormal development of a baby while it is in the womb, possibly as a result of genetic or hormonal factors, which causes the brain to develop a gender identity that is different to the baby's sexual organs.
Signs of gender dysphoria
The first signs of gender dysphoria can appear at a very young age. For example, a child may refuse to wear typical boys' or girls' clothes, or dislike taking part in typical boys' or girls' games and activities.
In most cases, this type of behaviour is just a normal part of growing up and will pass in time, but for those with gender dysphoria it persists into later childhood and through to adulthood.
Adults with gender dysphoria can feel trapped inside a body that does not match their gender identity. They may feel so unhappy about social expectations that they live according to their anatomical sex, rather than the gender they feel themselves to be. They may also have a strong desire to change or get rid of physical signs of their biological sex, such as facial hair or breasts.
If you think you or your child may have gender dysphoria, see your GP.
Your GP may refer you to a specialist team in a Gender Identity Clinic (GIC). Staff at these clinics can carry out a personalised assessment and provide any support you need. They can also offer advice about the treatment options available to you.
Treatment for gender dysphoria
Treatment for gender dysphoria aims to help reduce or remove the distressing feelings of a mismatch between biological sex and gender identity.
This can mean different things for different people. For some people, it can mean dressing and living as their preferred gender.
For others, it can mean taking hormones or having surgery to change their physical appearance.
Many trans people have treatment to change their body permanently, so that they are more consistent with their gender identity, and the vast majority are satisfied with the eventual results.
How common is gender dysphoria?
It's not known exactly how many people experience gender dysphoria, because many people with the condition never seek help.
A study carried out in Scotland in 1999 found that around 1 in every 12,500 people may have the condition, although some people believe this is a significant underestimate. A survey of 10,000 people undertaken in 2012 by the Equality and Human Rights Commission found that 1% of the population surveyed was gender variant, to some extent.
While gender dysphoria appears to be rare, the number of people being diagnosed with the condition is increasing, due to growing public awareness.
However, many people with gender dysphoria still face prejudice and misunderstanding.