Ambiguous Genitalia (Differences of Sex Development)

When sex development follows a less common path than one typical for a boy or a girl, the result is a difference of sex development (DSD*). Knowing at what point the path changed helps us provide appropriate medical care. 

Differences of sex development occur more frequently than most people realize. An estimated one in 4,500 children has such a condition. Many times, these differences are found at birth. Some aren’t found until later in the child’s life, even though the condition was present since early in development.

Human development is a complicated process. Slight differences in the usual process can result in a difference of sex development. Because these abnormal developments occur before birth, they are called congenital.

Three Key Times for DSD to Occur in Development

At Fertilization

When the egg from the mother meets the sperm from the father, the child’s chromosomal makeup is determined. The mother typically gives an X chromosome and the father either an X or Y chromosome. Usually, an XX individual is a girl and an XY is a boy. Sometimes, however, a child gets an extra chromosome from a parent or a chromosome is absent, resulting in XXY, XO or XYY. These differences lead to a DSD.

In Early Fetal Development

When a fetus is just forming in the mother’s uterus, an organ is present that we call the gonad. It is identical in girls and boys until midway through the second month of pregnancy. At that time, certain signals direct the gonad to develop into an ovary or a testicle. Any abnormality in these signals can lead to an abnormal gonad. For example, it may contain both ovarian and testicular tissue or may not produce hormones properly.

In Later Fetal Development

Further development leads to a child having organs — typically, a uterus, fallopian tubes, clitoris and labia in a girl or the seminal vesicles, penis and scrotum in a boy. At first, every fetus has the potential to develop either set of organs on the inside or outside. After the gonad becomes an ovary or a testicle, it makes hormones that help the body determine which type of structures to develop on the inside and outside. Variations in this development can lead to a range of abnormalities. For example:

  • A structure that may look like a small penis or a large clitoris
  • A penis with the opening at the base instead of the tip and no testes in the scrotum
  • An individual with testicles and male internal structures, but who looks female on the outside

Tests and exams help us know as precisely as possible what caused the difference. Understanding why the DSD occurred helps us to determine the best treatment for the child. Also, we use this information to help the family understand what to expect for their child. The precise cause cannot, however, always be determined.

A DSD brings a complex set of physical, medical and emotional challenges. The condition affects the child and parents. The care given at Lurie Children’s sensitively encompasses both. Like caring parents, our goal is a happy, healthy child and the best possible future for each individual in our care.

Detection & Diagnosis

A DSD can be detected and diagnosed at various times and ways during a child’s life.


Competent, collaborative multidisciplinary care assures the best possible outcome for a child with a DSD. Our team at Lurie Children’s combines pediatric endocrinologists, urologists, surgeons and nurses in addition to an ethicist and child psychologist experienced in DSD and gender issues.

Specialists & Experience

Our entire staff is dedicated to evaluating and treating pediatric patients from infancy through adolescence. Our specialists include:

  • Pediatricians
  • Endocrinologists
  • Urologists
  • Clinical psychologists
  • Psychiatrists
  • Ethics consultants
  • Nurse practitioner
  • School consultants
  • Social workers

Director Earl Cheng, MD is a board-certified pediatric urologist. Dr. Cheng completed his urology residency at Northwestern University and his pediatric urology fellowship at Children’s Memorial Hospital in Chicago. He is a national expert in complex reconstructive urology and has a special interest in the medical and surgical management of individuals with differences of sex development.

Meet all of our specialists

Make an Appointment

To find out more information about our program or to request an appointment, call Danielle Lee at 312.227.6203 or e-mail


Help us better understand the healthcare needs of adolescents and young adults who have a diagnosis of a difference of sex development (DSD). By joining our research study, you can help us learn more about opinions related to sexual health and fertility for individuals diagnosed with a DSD condition


Learn more about DSDs by visiting the following physician-recommended websites:

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Related Specialties

Ambiguous Genitalia (Differences of Sex Development)