Page last reviewed: 13/07/2011
Disorders of sex development (DSDs) are a group of conditions where the reproductive organs and genitals do not develop normally.
If you have a DSD, you will develop a mix or blend of male and female sexual characteristics. For example, you may be genetically female (with two X chromosomes) but have testes and an enlarged clitoris that resembles a penis.
The disorder occurs because there is a problem with your genetic make-up and/or how you respond to the sex hormones in your body.
It is not known how common DSDs are, but they are estimated to affect 0.1%-2% of the population.
Identifying a DSD
There are different types of DSD, and each has a different cause. Below are some examples.
Genetically female with male-looking genitals
Some people are genetically female with ovaries, but their genitals appear male. For example, they may have an enlarged clitoris resembling a penis and their labia (lips surrounding the vagina) may be fused together.
Doctors refer to this condition as 46,XX DSD.
The most common cause is a condition called congenital adrenal hyperplasia (CAH). If your child has CAH, they lack a particular enzyme (protein) that their body needs to make the cortisol and aldosterone hormones. Without these, the body produces more androgens (male sex hormones), which causes male characteristics to appear.
Genetically male with female-looking genitals
Some people are genetically male but their external genitals may appear female or somewhere between male and female. Testes may be absent or not properly formed.
Doctors refer to this condition as 46,XY DSD.
There are several different causes. One possible cause is androgen insensitivity syndrome, where the body ignores the androgens (male hormones) or is insensitive to them, so their genitals develop along female lines and their testes usually remain inside their body.
AIS is thought to occur in one in every 20,400 births, although the exact figures are unknown.
A mix of male and female characteristics
People with this type of DSD may have male chromosomes, female chromosomes or both. Physically, they have both ovarian and testicular tissue (for example, one ovary and one testis), and their genitals may appear female, male or a mix of both.
Doctors refer to this condition as 46,XX ovotesticular DSD.
Normally formed genitals but abnormal sexual development
Some people have neither the normal male (XY) or female (XX) set of chromosomes - for example, they may only have one X chromosome (XO), or they may have an extra chromosome (XXY).
Physically, their male sex organs are normally formed as either male (testes and a penis) or female (ovaries, womb and a vagina), but they may not go through normal sexual development at puberty.
Doctors refer to this condition as sex chromosome DSD.
An example is Turner syndrome,where a female is missing an X chromosome. Girls or women with Turner syndrome are usually infertile and their height is shorter than average.
Advice for parents
If you are concerned that your child may have a DSD, speak to your GP. They will be able to refer your child to a specialist, usually a consultant in paediatric endocrinology.
The consultant will then be able to introduce you to a team of different healthcare professionals who will work together to understand your child's condition and offer you and your child support and advice.
As your child grows up, they may need hormone therapy and psychological support. However, with the right care and support, many people with DSDs come to terms with their condition and live happily.
If you think you have a DSD.
If you think or know that you have a DSD condition, help and support is available.
You should speak to your GP, as they will be able to refer you to a team of healthcare professionals who will work together to understand your condition and offer you support and advice.
Most people with a DSD stay with the gender they were assigned as a baby, but if you feel that the gender you were assigned does not represent who you are, you may wish to change your gender.
If you do have a DSD, you may find that you are infertile and you may need hormone therapy and psychological support. With the right care and support, many people with DSDs come to terms with their condition and live normal lives.
Sex chromosomes are a collection of genes (called either X or Y) that play a vital role in our sexual development.
Women typically have two X chromosomes and men typically have one X and one Y chromosome.
It is the Y chromosome that stimulates the development of the male testes and stops the development of the female ovaries and womb.
When there is no Y chromosome, the female reproductive system and genitals develop.
Disorders of sex development (DSDs) were previously known as intersex conditions.
Some doctors also used to refer to a person with a DSD as a hermaphrodite. However, this term should no longer be used as it is misleading and can be insensitive to the women who are affected by the condition.
DSDs should not be confused with gender dysphoria, which is also known as transsexuality or being transgender. Gender dysphoria is where the reproductive organs and genitals have developed normally, but the person feels that their gender identity (their sense of what sex they are) does not match their biological sex.