Intersex Conditions (Differences of Sex Development)

Language and terminology

Many people prefer the terms intersex or differences of sex development, as some find "disorder" stigmatizing. Most people with these variations identify as men or women, and gender identity is separate from the physical variation. Clinicians aim to use the language each person and family prefers.

Main types

Congenital adrenal hyperplasia (CAH)

CAH is an inherited enzyme deficiency in the adrenal glands. It reduces cortisol and often aldosterone and increases androgens. In 46,XX babies, the genitals may look masculinized. In the salt-wasting form, babies of any sex can develop a life-threatening crisis with vomiting, dehydration and low sodium in the first weeks. Newborn screening in the US detects most cases.

Androgen insensitivity syndrome (AIS)

People with AIS have 46,XY chromosomes and testes, but their body cannot respond to testosterone. In complete AIS, the external genitals look typically female, and it is often discovered at puberty when periods do not start, or from a groin lump. Partial AIS causes a range of appearances.

How intersex conditions are found

• At birth: atypical genitals, undescended testes on both sides, or severe hypospadias with an undescended testis.
• Before birth: a mismatch between prenatal genetic testing and ultrasound findings.
• At puberty: absent or unexpected pubertal changes, or absent periods.
• In adulthood: infertility testing.

Diagnosis

Assessment is done by a specialist DSD team. Tests may include:

• chromosome analysis (karyotype) and genetic tests, often a panel or exome sequencing
• hormone tests: 17-hydroxyprogesterone for CAH, testosterone, DHT, AMH, LH and FSH, and electrolytes
• pelvic ultrasound or MRI to look for a uterus and gonads
• stimulation tests to see how the gonads or adrenal glands respond
• sometimes laparoscopy to examine gonads

In newborns, sex assignment is usually delayed briefly until key results are available, with the family fully involved.

Care and treatment

Modern care follows principles from international consensus statements:

• Multidisciplinary team: pediatric endocrinology, urology or surgery, gynecology, genetics, psychology and nursing.
• Medical treatment: lifelong glucocorticoid and mineralocorticoid replacement in CAH, puberty induction or hormone replacement when gonads do not produce enough hormones, and fertility preservation options where possible.
• Gonadal management: some gonads carry a raised cancer risk (for example, dysgenetic gonads with Y chromosome material), which may require monitoring or removal. Timing is individualized.
• Surgery: decisions about genital surgery are increasingly delayed until the person can participate, unless surgery is needed for health reasons such as urinary function. This is an area of active debate and varying practice.
• Psychological support: for the person and family, from diagnosis through adolescence and adulthood.
• Honest information: age-appropriate disclosure and access to medical records.
• Peer support groups connecting families and individuals.

Outlook

Most people with intersex variations lead healthy, full lives. Long-term health needs depend on the specific condition and may include hormone therapy, monitoring for bone health, fertility support and psychological care. Transition to adult services should be planned.

Frequently asked questions

What does intersex mean?

Intersex describes people born with variations in chromosomes, gonads, hormones or genital anatomy that do not fit typical definitions of male or female. Medically these are called differences of sex development. Many intersex variations are not visible at birth.

What is the most common cause of atypical genitals at birth?

Congenital adrenal hyperplasia is the most common cause in babies with 46,XX chromosomes. It also needs prompt treatment because some forms cause a dangerous salt-wasting crisis in the first weeks of life.

How are intersex conditions diagnosed?

Doctors use chromosome and genetic tests, hormone measurements and imaging such as ultrasound or MRI. A specialist team interprets results together with the family. Some conditions are found only at puberty or during infertility testing.

Do intersex conditions need surgery?

Not always. Surgery may be needed for health reasons, such as urinary problems or gonadal cancer risk. Cosmetic genital surgery in infancy is increasingly postponed so the person can be involved in the decision when older.

Are intersex conditions inherited?

Some are. Congenital adrenal hyperplasia and androgen insensitivity syndrome are inherited, and siblings may be affected. Others, such as Turner and Klinefelter syndromes, usually occur by chance. Genetic counseling helps families understand recurrence risks.