Androgen insensitivity syndrome

Androgen insensitivity syndrome (AIS) is a rare condition that affects the development of a child's genitals and reproductive organs.

A child born with AIS is genetically male, but the external appearance of their genitals may be female or somewhere between male and female.

Someone with AIS may benefit from psychological support, and in some cases may have treatment to alter the appearance of their genitals.

Most people born with the condition are unable to have children, but they'll otherwise be perfectly healthy and able to lead a normal life.

What causes AIS?

AIS is caused by a genetic fault that's usually passed on to a child by their mother.

Despite being genetically male, the body doesn't respond to testosterone (the male sex hormone) properly and male sexual development doesn't happen as normal.

The penis doesn't form or is underdeveloped, which means the child's genitals may appear female, or between male and female. However, they don't have a womb or ovaries and have fully or partially undescended testicles.

Women who carry the genetic fault won't have AIS themselves, but there's a 1 in 4 chance each child they have will be born with the condition.

Types of AIS

There are 2 main types of AIS, which are determined by how much the body is able to use testosterone. These are:

complete androgen insensitivity syndrome (CAIS) – where testosterone has no effect on sexual development, so the genitals are entirely female
partial androgen insensitivity syndrome (PAIS) – where testosterone has some effect on sexual development, so the genitals are often between male and female

PAIS is usually noticed at birth because the genitals appear different.

CAIS can be more difficult to spot, as the genitals usually look normal for a girl. It's often not diagnosed until puberty, when periods don't start and pubic and underarm hair doesn't develop.

Read more about the symptoms of AIS and diagnosing AIS.

Living with AIS

Children with AIS and their parents are supported by a team of specialists, who will offer ongoing care and support. They'll help you decide whether to raise your child as a girl or a boy while they're still very young.

Most children with CAIS are raised as girls, while those with PAIS can be brought up either as girls or boys. It's up to you as a parent, with help from specialists, to decide what you think is in the best interests of your child.

Once you've decided, you can learn about the treatments available that can help make your child's body look more consistent with the chosen gender and help them develop more naturally.

This may involve surgery to alter the appearance or function of their genitals, and hormone treatment to encourage female or male development during puberty.

Support and advice

You and your child will be offered psychological support to help you understand and cope with the diagnosis of AIS. Children may not need psychological support while they're very young, but they usually do as they get older.

You'll be given advice about how and when to discuss the condition with your child.

You may also find it helpful to get in touch with a support group, such as DSD Families.

Gender identity and gender dysphoria

Most children with AIS grow up to feel they are the gender their parents chose to raise them as. This feeling is known as their gender identity.

In a few cases, older children and adults with AIS feel their gender identity doesn't match the gender they've been raised as. This is known as gender dysphoria.

People with gender dysphoria often have a desire to live as a member of the opposite sex, and may want treatment to make their physical appearance more consistent with their gender identity.

If your child is diagnosed with AIS, you should be told about the issues of gender identity that could arise as your child gets older.

National Congenital Anomaly and Rare Diseases Registration Service

If your child has AIS, your clinical team will pass information about them on to the National Congenital Anomaly and Rare Diseases Registration Service (NCARDRS).

The NCARDRS helps scientists look for better ways to prevent and treat AIS. You can opt out of the register at any time.

Page last reviewed: Fri Nov 2021 Next review due: Fri Nov 2021