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Differences of Sex Development

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. 


Sex development occurs in stages. A fetus has many opportunities to develop along a path that is not the typical one for a boy or a girl. When a less common path of sex development is followed, the result is a difference of sex development (DSD). Knowing at what point the path changed helps us provide appropriate medical care. 

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 D​evelopment

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.

Current Terminology

The way people refer to individuals with DSDs has changed over the last 20 years. 

“We no longer use terms like ‘hermaphrodite’ or even ‘intersex’ because they may convey inappropriate, incomplete or inaccurate information,” explains Joel E. Frader, MD, Head of Academic General Pediatrics and Primary Care. He is also the A Todd Davis Professor of General Academic Pediatrics, Professor of Pediatrics and Professor of Medical Humanities and Bioethics at Northwestern University Feinberg School of Medicine.

“Some of the old terms stigmatized individuals with a DSD and created hurt feelings, at times leading to social isolation. DSD simply identifies that the person has a medical condition — one of literally dozens of possibilities — that needs careful attention to precisely diagnose; explore the personal, sexual and reproductive implications of the difference and identify the support needed for good family and personal decision making and emotional health.”

Diagnosis & Treatment

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.

To provide optimal care for each child, we work with other specialists, including neonatologists, geneticists and pediatric gynecologists. Read more abour our diagnosis and treatments.


A diagnosis of a DSD can be overwhelming, upsetting and frightening for any family. The team at Lurie Children’s is committed to providing the most up-to-date care in a setting that is supportive and compassionate for your family. Our specialists are dedicated to working with your family and understanding your beliefs and your hopes for your child.

As children grow from infancy to adolescence to adulthood, their medical and social needs change, and we work to usher them through this development as smoothly as possible. Overall, our goal is for each child to have optimal emotional well-being, growth, development and future sexual function along with a stable gender identity.


Lurie Children’s Gender and Sex Development Program  for children and families affected by DSD and gender identity is now accepting patients. We look forward to welcoming more families. 


The creation of the  Gender and Sex Development Program at Lurie Children’s was made possible, in part, through private contributions. Your support is vital in helping us continue to make a difference in the lives of all of our patients and families. 

Lurie Children’s relies on philanthropic funding to enhance its programs, services and research for children. To learn more, please contact Ann & Robert H. Lurie Children’s Hospital of Chicago Foundation at, call 312.227.7251 or make a gift today.


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

​Join New DSD Research Study

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. Find out more.