Atypical genitalia in neonates

Last reviewed: 2 Sep 2023
Last updated: 04 Apr 2023



History and exam

Key diagnostic factors

  • atypical genitalia with no palpable gonads
  • atypical genitalia with one palpable gonad
  • atypical genitalia with bilaterally palpable gonads
  • penile length <2.5 cm in a phenotypic male
  • clitoris >1 cm in a phenotypic female
  • hypospadias and undescended testes or separation of scrotal sacs
  • urethral opening at base of phallus
More key diagnostic factors

Other diagnostic factors

  • hypotension and vomiting
  • dysmorphic facial features
Other diagnostic factors

Risk factors

  • family history
More risk factors

Diagnostic investigations

1st investigations to order

  • chromosome analysis (karyotype)
  • serum electrolytes and glucose
  • pelvic ultrasound
More 1st investigations to order

Investigations to consider

  • serum 17 hydroxyprogesterone
  • plasma renin activity
  • serum 11 deoxycortisol and 11 deoxycorticosterone
  • serum testosterone
  • serum dihydrotestosterone
  • serum LH and follicle-stimulating hormone (FSH)
  • adrenocorticotropic hormone (ACTH) stimulation test
  • human chorionic gonadotropin (hCG) stimulation test
  • anti-Müllerian hormone (AMH)
  • urine steroid profile
More investigations to consider

Treatment algorithm


all neonates presenting with atypical genitalia


46,XX: congenital adrenal hyperplasia secondary to 21 hydroxylase deficiency (at presentation)


45,X/46,XY mixed gonadal dysgenesis


46,XX: congenital adrenal hyperplasia secondary to 21 hydroxylase deficiency (following sex assignment)


45,X/46,XY mixed gonadal dysgenesis



Justin H Davies, MD, FRCPCH, MRCP

Consultant Paediatric Endocrinologist

Hon. Associate Professor

University of Southampton




JD is associate editor for the Journal of Paediatric Endocrinology and Metabolism; has travel bursaries from SANDOZ, Kwyo Kyrin, and Novo Nordisk; and has developed educational materials for Kwyo Kyrin. JD completed tenure as chair of the British Society for Paediatric Endocrinology in Nov 2020.


Dr Justin Davies would like to gratefully acknowledge Dr Gemma Watts and Dr Ingrid A. Holm, previous contributors to this topic. IAH and GW declare that they have no competing interests.

Peer reviewers

Paul Saenger, MD, MACE

Professor of Pediatrics

Department of Pediatrics (Endocrinology)

Montefiore Medical Center

Albert Einstein College of Medicine

New York



PS declares that he has no competing interests.

Mary M. Lee, MD

Professor of Pediatrics and Cell Biology

Vice-Chair of Academic Affairs in Pediatrics

Pediatric Endocrine Division

UMass Medical School




MML declares that she has no competing interests.

Patricia Y. Fechner, MD

Associate Professor Pediatrics

Pediatric Endocrinology

University of WA

Medical Director of DSD Program

Seattle Children’s Hospital




PYF declares that she has no competing interests.

  • Atypical genitalia in neonates images
  • Differentials

    • Micropenis due to another cause
    • Unilateral undescended testis (cryptorchidism)
    More Differentials
  • Guidelines

    • Guidelines on paediatric urology
    • UK guidance on the initial evaluation of a suspected difference or disorder of sex development (revised 2021)
    More Guidelines
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