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Health condition · Clinically reviewed

Atypical genitalia, differences of sex development and modern, affirming UK care.

Natural variations in sex characteristics deserve calm, expert assessment, honest information, peer support and, where possible, decisions the person can be part of.

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Why trust this guide

  • 01

    Affirming and accurate

    Written with input from clinicians and reviewed against current UK specialist guidance and patient-advocacy consensus.

  • 02

    Sourced from guidance

    Checked against the Chicago 2005 consensus, BSPED, BAPU and peer-reviewed sources listed at the end.

  • 03

    Current for 2026

    Reflects modern UK multidisciplinary DSD care, delayed elective surgery principles and patient autonomy.

Key facts

Atypical genitalia at a glance.

The essentials in plain English. What "differences of sex development" means, why language matters and how modern UK care is organised.

  • What it is

    Variations in sex characteristics where genital, gonadal or chromosomal anatomy does not fit typical binary expectations. Natural human variations, not disorders of the person.

  • Preferred language

    Differences of sex development (DSD) or intersex traits. "Ambiguous" is now avoided as it centres the observer rather than the person.

  • Categories

    Sex chromosome DSD, 46,XY DSD, 46,XX DSD (including congenital adrenal hyperplasia) and ovotesticular variations, per the Chicago 2005 consensus.

  • Neonatal emergency

    Salt-wasting CAH can present in the first two weeks of life with vomiting, poor feeding and collapse. Endocrine emergency.

  • MDT care

    Every child deserves a specialist DSD multidisciplinary team, peer support and delayed elective surgery decisions where clinically safe.

  • Autonomy

    International consensus increasingly favours deferring irreversible cosmetic genital surgery until the person can consent for themselves.

Why this guide matters

Calm expertise, honest language, patient-led decisions.

Differences of sex development have long carried unnecessary stigma. Modern UK care centres the person, defers what can safely wait, and treats what needs treating.

  • These are natural variations

    Variations in sex characteristics are part of the range of human biology. Some need medical care. None make the person less whole.

  • CAH can be a true emergency

    Salt-wasting congenital adrenal hyperplasia in the first two weeks of life is treatable but time-critical. Every newborn deserves careful screening.

  • Autonomy shapes modern care

    Where surgery is not medically urgent, UK specialist teams increasingly favour deferring elective procedures until the young person can be part of the decision.

Chicago 2005 consensus

The four broad categories of DSD.

The 2005 international consensus reframed the field around biology rather than binary expectations. These are the recognised groupings.

  • Sex chromosome DSD

    Turner syndrome (45,X), Klinefelter syndrome (47,XXY), mixed gonadal dysgenesis and ovotesticular DSD.

  • 46,XY DSD

    Includes androgen insensitivity syndrome (complete or partial), 5-alpha-reductase deficiency, gonadal dysgenesis and testosterone biosynthesis defects (Leydig cell hypoplasia, 3-beta-HSD, 17-hydroxylase deficiency).

  • 46,XX DSD

    Congenital adrenal hyperplasia (most commonly 21-hydroxylase deficiency, around 90 percent), androgen exposure in utero, ovotesticular DSD and Mullerian agenesis (MRKH).

  • Salt-wasting CAH

    A subset of 46,XX DSD that is a neonatal endocrine emergency. Presents days 5 to 14 of life with vomiting, poor feeding, hyponatraemia and hyperkalaemia.

How the assessment is made

From newborn exam to a considered plan.

The steps a UK specialist DSD team will normally follow. Nothing is rushed. Sex assignment and elective surgery decisions are made together, not in the first hours.

  1. 01

    First hours

    Sensitive newborn exam

    A calm, private assessment of clitoral or phallic size, urethral opening, labial or scrotal fusion and palpable gonads. Language and dignity matter from minute one.

  2. 02

    First hours

    Urgent MDT referral

    Every suspected DSD is referred to a specialist paediatric endocrine, urology, genetics, psychology, neonatology and ethics team. No sex assignment until the MDT has met.

  3. 03

    First hours

    CAH salt-wasting screen

    Bloods for 17-hydroxyprogesterone, electrolytes, glucose, cortisol, ACTH, renin, androstenedione and testosterone. Salt-wasting is life-threatening.

  4. 04

    First days

    Karyotype and molecular panel

    Urgent karyotype, then targeted gene testing (CYP21A2, AR, SRD5A2, NR5A1, SRY, WT1, SF1) guided by early findings.

  5. 05

    First days

    Pelvic imaging

    Ultrasound of internal structures, then MRI, cystourethrogram or genitogram as needed to map uterus, gonads and urogenital sinus.

  6. 06

    First days

    Hormone profile

    AMH, inhibin B, LH, FSH and androgen precursors help clarify gonadal function and the underlying diagnosis.

  7. 07

    Together

    Sex assignment conversation

    A careful, unhurried MDT discussion with parents. The child's eventual autonomy is paramount, and elective irreversible surgery is deferred where possible.

Typical timeline: MDT input within 24 hours, working diagnosis within days, an unhurried plan within weeks.

Presentation

How DSD can present.

Newborn findings are the most familiar, but many variations are recognised later in childhood, at puberty or in adulthood.

  • Clitoromegaly or micropenis

    Enlargement of the clitoris or a smaller than expected phallus. Measured with care against age-based norms.

  • Hypospadias

    Urethral opening on the underside of the phallus. Ranges from glanular to perineal and often part of a wider picture.

  • Bifid scrotum or labial fusion

    Partial fusion of the labia or a divided scrotal appearance. Common in virilised 46,XX or under-virilised 46,XY infants.

  • Non-palpable or inguinal gonads

    Absent gonads in the scrotum, or gonads felt in the groin or labia. Always warrants urgent assessment.

  • Salt-wasting crisis

    Vomiting, poor feeding, weight loss, hyponatraemia and hyperkalaemia in the first two weeks of life. A neonatal emergency for CAH.

  • Primary amenorrhoea

    No periods by 15, with or without breast development. A common late presentation of AIS or Mullerian agenesis.

  • Inguinal hernia in a girl

    A hernia containing a gonad in an infant or girl can be the first sign of complete androgen insensitivity syndrome.

  • Red flag - neonatal collapse

    A drowsy, dehydrated or shocked newborn with any atypical genital feature needs immediate paediatric input for suspected CAH.

Care and support

How DSD is cared for in the UK.

Specialist multidisciplinary teams, careful hormone replacement where needed, and increasingly cautious, patient-led surgical decisions.

  • DSD multidisciplinary team

    Paediatric endocrine, urology, genetics, psychology and ethics working together. Specialist UK centres include GOSH, UCLH, Birmingham Children's, Bristol and Alder Hey.

  • CAH hormone replacement

    Lifelong hydrocortisone and, where salt-wasting, fludrocortisone plus salt. Emergency steroid card and sick-day rules save lives.

  • Puberty induction

    Where needed, carefully timed oestrogen or testosterone to induce puberty in a way that aligns with the young person's identity and wishes.

  • Gonadal management

    Decisions on retaining, monitoring or removing gonads are individualised and increasingly delayed until the person can be part of the choice.

  • Elective genital surgery

    Cosmetic or reconstructive surgery on children is now approached with caution. Elective procedures are deferred where clinically safe, in line with ethical consensus.

  • Fertility preservation

    Where appropriate, sperm or oocyte banking and gonadal tissue preservation are discussed early, with counselling.

  • Psychological support

    Lifelong access to specialist psychology for the young person and their family. Peer support through Intersex UK, dsdfamilies, AISSG UK and CAH Support Group.

  • Adult transition clinic

    A planned handover to adult endocrine, urology, gynaecology, reproductive medicine and psychology so care never falls through the gaps.

Ethics and autonomy

A global movement toward deferred elective surgery.

The Yogyakarta Principles plus 10, Council of Europe guidance and a growing international consensus argue against irreversible cosmetic genital surgery on children who cannot consent. Malta legislated first in 2015, Germany followed in 2021. UK specialist teams increasingly reflect this in practice.

What this guide is based on

The sources behind every claim on this page.

International consensus, UK specialist society standards and human-rights frameworks, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your specialist DSD team knows your child and family and can tell you which parts apply to you. If in doubt, ask them.

  • Hughes IA et al. Consensus statement on management of intersex disorders (Chicago 2005 / LWPES-ESPE).

  • British Society for Paediatric Endocrinology and Diabetes (BSPED). DSD guidance.

  • British Association of Paediatric Urologists (BAPU). Position statements on paediatric genital surgery.

  • Royal College of Paediatrics and Child Health (RCPCH). Care of children with DSD.

  • Council of Europe and Yogyakarta Principles plus 10 on the rights of intersex people.

Red flags

When to seek urgent specialist input.

Most DSD care is planned and unhurried. These are the situations where speed matters, or where a specialist opinion should not wait.

  • Salt-wasting CAH crisis

    Vomiting, poor feeding, drowsiness and shock in a newborn is a medical emergency. Immediate hydrocortisone, fluids and glucose can be life-saving.

  • Bilateral non-palpable gonads

    In an apparently male infant, absent scrotal gonads plus any atypical feature is treated as CAH until proven otherwise.

  • Inguinal hernia containing a gonad

    In a girl or infant, a hernia with a gonad inside should prompt karyotype and specialist review for possible AIS.

  • Delayed or absent puberty

    No breast development by 13, no periods by 15, or arrest of puberty deserves endocrine assessment and imaging.

  • Unplanned virilisation

    New voice deepening, clitoromegaly or hirsutism in a child or adolescent warrants urgent endocrine review.

  • Psychological distress

    The young person or family struggling with diagnosis, identity or past medical experiences deserves prompt access to specialist psychology.

  • Historic non-consensual surgery

    Adults revisiting past childhood surgery need trauma-informed care, honest access to their records and specialist psychological support.

  • Fertility concerns

    Any decision that could affect future fertility (gonadectomy, hormone therapy) should trigger a fertility preservation conversation first.

  • Lost to follow-up

    A young person on lifelong steroids or hormone therapy who has disengaged from care needs proactive recall and support.

Living with it

A life shaped by the person, not the diagnosis.

Four things that make the biggest difference day to day. Language that respects the person, a named specialist team, peer support and a care model that centres autonomy.

A quiet reminder

There is no rush to a single answer.

Good specialist care makes space to gather information, ask questions and take the decisions that need taking, one at a time.

  1. 01 Language

    Words that respect the person

    Use "variations in sex characteristics" or "DSD" and follow the person's own lead. Avoid "ambiguous", "disorder" or "abnormal".

  2. 02 Team

    A named MDT and a plan

    A specialist DSD team, a clear care plan and a single point of contact make the biggest difference to families day to day.

  3. 03 Peers

    You are not alone

    Intersex UK, dsdfamilies, AISSG UK and CAH Support Group offer connection, information and community from people who have lived it.

  4. 04 Autonomy

    The person leads their own care

    Where clinically safe, elective decisions wait until the young person can be part of them. Their voice comes first.

Frequently asked

The questions families and adults ask us most.

Honest, plain-English answers about language, first steps, CAH, surgery and support.

  • What does "atypical genitalia" mean?

    It describes external or internal genital anatomy that does not fit typical binary expectations at birth. Preferred terms today are "differences of sex development" (DSD) or "intersex traits". These are natural variations in human biology, not something wrong with the person, though medical assessment is important to check for underlying hormonal or structural issues.

  • Is this the same as being transgender?

    No. Being intersex or having a DSD is about physical variation in sex characteristics present from birth. Being transgender is about a person's gender identity. The two are separate, though some people are both. Care and language should always follow the person's own lead.

  • What happens straight after birth?

    A calm, private examination and urgent referral to a specialist DSD multidisciplinary team. Bloods are taken to rule out life-threatening salt-wasting CAH, and imaging and genetic tests are arranged. Sex assignment is not rushed and is made with the family and the specialist team together.

  • Should surgery be done in childhood?

    International ethical and patient-advocacy consensus is moving strongly against irreversible cosmetic genital surgery on children who cannot yet consent. Where surgery is not medically urgent, most UK specialist teams now favour deferring elective procedures until the young person can be part of the decision.

  • What is congenital adrenal hyperplasia (CAH)?

    CAH is the most common cause of 46,XX DSD, usually due to 21-hydroxylase deficiency. In its salt-wasting form it is a neonatal endocrine emergency needing lifelong hydrocortisone, fludrocortisone, salt and an emergency steroid card. With good care, outcomes for growth, puberty and fertility are excellent.

  • Where can families and adults get support in the UK?

    Specialist care is available at centres including Great Ormond Street, University College London Hospitals, Birmingham Children's Hospital, Bristol Royal Hospital for Children and Alder Hey. Peer support is offered by Intersex UK, dsdfamilies, AISSG UK and the CAH Support Group. Adult transition clinics coordinate endocrine, urology, gynaecology, reproductive and psychological care.

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