Health Library

Androgen Insensitivity Syndrome (AIS)

What Makes a Person’s Body Develop on a Male or Female Path?

There are many factors that are important for how the body develops. These include genetics and hormones. Genetics are instruction codes and hormones are chemical messengers. In terms of genetics, there are two chromosomes, the X and one Y chromosomes, that guide how the reproductive parts development. Most boys have one X and one Y chromosome. Most girls have two X chromosomes.

In terms of hormones, two important hormones are testosterone and estrogen. They are made by glands called gonads. There are two types of gonads: testicles and ovaries. Testicles make testosterone and some estrogen. Ovaries make estrogen and some testosterone. Before birth, testosterone usually makes bodies develop on a male path. People whose bodies do not make large amounts of testosterone develop on a female path. Some people’s bodies make testosterone but do not respond to it. Their bodies may also develop as girls. Later, at puberty, hormones make the body change again.

How a person’s body grows and develops (their “sex”) is not the same as their “gender”. “Gender” is about a person’s sense of self. It is about their inner feeling of being a boy/man, girl/woman, both, or neither.

Learn more about Gender and Sex: What Makes a Person a Boy or a Girl?

What Are The Types of AIS?

There are two types of AIS: Complete and Partial AIS (CAIS and PAIS). The type that a person has depends on how much their body responds to androgens. People with CAIS do not respond at all to androgens. People with PAIS, respond partially to androgens.

When a person has PAIS, their body responds partially to androgens. Depending on how much their body responds to androgens, their genitals may be more female, more male, or both female and male.

During puberty, people with PAIS may grow some pubic or armpit hair. Their voice may change. They may develop breasts, but do not have periods.

Table. Genital findings in people with AIS

What Are The Signs of AIS?

• CAIS and PAIS may be suspected before birth due to prenatal testing or a family history.
• PAIS may be suspected in babies based on how their genitals look. Both PAIS and CAIS may be suspected at any age during a routine checkup because a doctor feels bumps in the groin.
• CAIS may be suspected a puberty when girls do not start their periods.

How is AIS Diagnosed?

The doctors may order tests, such as:

• Karyotype: This is a blood test that looks at all of the body’s chromosomes, including the X and Y chromosomes.
• Genetic testing: This is a blood test to look for changes in the gene that causes AIS.
• Hormone testing: This is a blood test that checks what hormones the gonads are making and how much.
• Pelvic ultrasound: This is an imaging test that looks for the gonads and for a uterus.
• Laparoscopy: This is a surgery using a small camera. The surgeon looks for the reproductive parts inside the body. The surgeon may also take small pieces of tissue for testing.

How Do We Treat and Care for People with AIS?

We care for people with CAIS and PAIS as a team of specialists working together. Our team has specialists in endocrinology, gynecology, urology, psychology, genetics, ethics, social work and child life. Care and treatment plans depend on each patient’s individual needs. Treatment involves regular clinic visits. At each visit, we check growth and development. We also address patients’ and families’ needs at different ages and stages of life. Some patients may need to take hormones.

Our team helps patients and families understand and weigh treatment options. Options may include, decisions about taking hormones and moving or removing gonads.

Our team provides support and counseling to our patients and families. We want all patients and families to experience their best quality of life.