Overview
Penile agenesis, also called aphallia or penile aplasia, is a very rare condition where a baby is born without a penis. This happens when the penis does not form properly during early pregnancy, usually between weeks 3 and 6 of fetal development. The condition affects genetic males (those with XY chromosomes), though the external appearance at birth may look different from a typical male. The urethra, which is the tube that carries urine out of the body, is usually present but opens in an abnormal location, often near the rectum or perineum. The testes may be present but are often undescended, meaning they have not moved into their normal position. Because of the way the body looks at birth, many children with penile agenesis have historically been raised as girls, though this practice is now being reconsidered in favor of more individualized, patient-centered care. Associated problems can include kidney and urinary tract abnormalities, and sometimes issues with other organs. Treatment is complex and involves a team of specialists. Surgical options exist to help with urinary function and, in some cases, to create genital structures. Hormone therapy and psychological support are also important parts of care. Decisions about gender assignment and surgical intervention are deeply personal and are now made collaboratively with families and, as the child grows, with the patient themselves.
Also known as:
Key symptoms:
Absent penis at birthUrethra opening in an abnormal location, such as near the rectum or perineumUndescended testes (testes not in their normal position)Difficulty or abnormal pattern of urinationPossible kidney or urinary tract abnormalitiesPossible abnormalities of the scrotumAmbiguous or atypical genital appearance at birth
Clinical phenotype terms (29)— hover any for plain English
Sporadic
Usually appears on its own, not inherited from a parent
Neonatal
Begins at or shortly after birth (first 4 weeks)
FDA & Trial Timeline
3 eventsHospices Civils de Lyon — NA
Namik Kemal University
Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
No FDA-approved treatments are currently listed for Penile agenesis.
View clinical trials →Clinical Trials
View all trials with filters →No actively recruiting trials found for Penile agenesis at this time.
New trials open frequently. Follow this disease to get notified.
Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to Penile agenesis.
Community
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Start the conversation →Latest news about Penile agenesis
Disease timeline:
New recruiting trial: Human Penile Allotransplantation
A new clinical trial is recruiting patients for Penile agenesis
Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
Rare disease caregiving can be isolating. Connect with counseling and peer support.
Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Questions for your doctor
Bring these to your next appointment
- Q1.What tests do we need to do right away to make sure my child's kidneys and urinary tract are healthy?,What are the surgical options available, and when would you recommend them?,How should we approach decisions about gender assignment, and what does current evidence say?,What psychological support is available for our child and our family?,Are there any associated conditions or syndromes we should be tested for?,What does long-term follow-up look like, and which specialists will be involved?,Are there patient or family support groups you would recommend for families dealing with this condition?
Common questions about Penile agenesis
What is Penile agenesis?
Penile agenesis, also called aphallia or penile aplasia, is a very rare condition where a baby is born without a penis. This happens when the penis does not form properly during early pregnancy, usually between weeks 3 and 6 of fetal development. The condition affects genetic males (those with XY chromosomes), though the external appearance at birth may look different from a typical male. The urethra, which is the tube that carries urine out of the body, is usually present but opens in an abnormal location, often near the rectum or perineum. The testes may be present but are often undescended,
How is Penile agenesis inherited?
Penile agenesis follows a sporadic inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Penile agenesis typically begin?
Typical onset of Penile agenesis is neonatal. Age of onset can vary across affected individuals.
Which specialists treat Penile agenesis?
18 specialists and care centers treating Penile agenesis are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.