Differences of Sex Development

Sex development occurs in stages. Babies have many opportunities to develop along paths that are not typical for male or female development. When sex development follows a less common path, the result is a difference of sex development (DSD*). Knowing at what point the path changed helps us provide appropriate medical care. 

*DSD is a term in evolution. Commonly used terms to describe DSD conditions include difference of sex development, disorder of sex development, variations of sex characteristics, and intersex.

Differences of sex development occur more frequently than most people realize. An estimated one in 4,500 children has such a condition. While many times, these differences are found at birth, some are not found until later in life, even though these conditions are 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 developmental differences occur before birth, they are called congenital.

Three Key Times for DSD to Occur in Development

At Fertilization

When an egg and sperm meet, the child’s chromosomal makeup is determined. One parent typically gives an X chromosome and the other either an X or Y chromosome. Usually, an XX individual is a female and an XY individual is a male. 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 during the pregnancy, an organ is present that we call the gonad. It is identical in females and males 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 change in these signals can lead to a gonad that doesn’t develop in the typical way. 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 for females or the seminal vesicles, penis and scrotum for males. 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 differences. 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 affecting both the child and parents. The approach to care at Lurie Children’s is to address all of these needs in a sensitive manner. Our goal is a happy, healthy child and the best possible future for each individual in our care.


A diagnosis of a DSD can be overwhelming, and the team at Lurie Children’s is committed to providing supportive and compassionate care for your family. Our specialists are dedicated to working with patients and families to understand patient’s hopes and goals for the future.

As children grow from infancy to adolescence to adulthood, their medical and social needs evolve. The Sex Development Program’s multidisciplinary staff collaborates with patients as they transition into adolescents to ensure that they have accurate information and continued access to supportive and comprehensive care.

Detection & Diagnosis

A DSD can be detected and diagnosed for a variety of reasons and at different times in a patient’s life.


Competent, collaborative multi-disciplinary care assures the best possible outcome for a child with a DSD. Our team includes multidisciplinary specialists, all of whom have specific expertise in gender and sex development.

Specialists & Experience

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

  • Endocrinologists
  • Urologists
  • Pediatric surgeons
  • Clinical psychologists
  • Genetic counselors
  • Ethics consultants
  • Social workers
  • Nurses 
  • Health educators

Make an Appointment

To find out more information about our program or to request an appointment, call 312.227.6203.


If you or your child are interested in learning about potential studies you may be eligible for, please contact Josie at 312.227.6076 or Ashley at 312.227.6954


Many families also find significant support from trusted family members, friends, support groups, advocacy organizations and their religious support system. Below are resources with additional information: 

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