What are Differences of Sex Development (DSD)?
Differences of sex development (DSD) are a group of conditions that occur before birth and that affect how the reproductive body parts grow and develop. Some people may use other words for this, like variation in sex characteristics, or intersex, or use the name of the actual condition.
There are two main things that decide whether a baby develops in male or female way: genetic factors and sex hormones. The reproductive body parts may develop differently if there is a change in any of the factors needed for sex development. This results in DSD.
Background
“Sex” is about a person’s body parts and how their body grows and develops. A person’s sex is due to a mix of genes and hormones.
Genes
Chromosomes are large groups of genes. You can think about genes as instruction codes that are packaged in a person’s chromosomes. There are some genes that are involved in sex development.
Most people have 46 chromosomes. Two of the chromosomes, the X and the Y, are called sex chromosomes. Most boys have one X and one Y chromosome. Most girls have two X chromosomes. However, some people may have different chromosome patterns. For example, some girls have one X and one Y chromosome. Variations in some genes or chromosome patterns may explain how some people’s bodies develop differently.
Hormones
Hormones are chemical messages that a person’s body makes. They tell the body how to grow and develop. Sex hormones make a person’s body parts develop, both before a baby is born and at puberty. Gonads are parts of the body that make sex hormones. Gonads can grow as testicles or ovaries, or sometimes a combination of both (ovotestes). Most boys have testes and most girls have ovaries. Genetic factors (for example, if a Y chromosome is present or not) are important for gonads to develop into testicles or ovaries. Testicles make hormones called androgens, like testosterone. Ovaries make mostly estrogen, and some testosterone. In addition, testicles make sperm and ovaries make eggs. Variations in sex chromosomes and genes may affect how the gonads develop and the hormones they make. Sometimes ovaries or testicles do not develop and do not make hormones.
Reproductive Body Parts
People have reproductive parts inside and outside their bodies. Gonads are one of the parts inside the body. Also inside the body, most girls have a vagina, a cervix and a uterus. People with DSD can have a variation in how these reproductive parts develop (variations in size, shape, length, for example). The parts outside the body are called genitals. There is a wide range in how the genitals can develop before birth. Most boys have a penis and a scrotum. Most girls have a clitoris, labia and an opening that leads to the vagina. People with DSD can have genitals that develop in the range between male (penis/scrotum) and female (clitoris/labia).
What causes Differences of Sex Development?
There are reasons why people may have a DSD. These may be a variation in any of the following:
- Chromosomes or genes
- Gonads (testicles or ovaries)
- Hormones
When are Differences of Sex Development Suspected?
People are born with DSD. Sometimes the DSD is found at birth, and other times during childhood, puberty or less commonly adulthood. The DSD may be found if there is a variation in the genitals or the reproductive body parts. Some DSD conditions are associated with other health issues.
Some examples of when DSD may be found:
- Genitals do not look typical such as:
- Large clitoris
- Small penis
- Hypospadias (the hole for urination is at the base of the penis, instead of the tip)
- Absent testicles in a boy
- Sex chromosomes that do not match how the genitals look (which can be found out before baby is born by ultrasound or prenatal genetic testing, or later in life)
- Puberty that does not happen as expected or periods that don’t start
- Infertility in adulthood
How are Differences of Sex Development Diagnosed?
Doctors may order tests, such as:
- Karyotype: This is a blood test that looks at a person’s chromosomes, including the X and Y chromosomes.
- Genetic testing: This is a blood test to look for changes in the genes that are known to cause DSD.
- Hormone testing: This is a blood test that checks what hormones the gonads are making and how much.
- Pelvic (or groin) ultrasound: This is an imaging test that looks for the gonads inside the body and for a uterus.
- Cystoscopy/Vaginoscopy: This is a procedure using a small camera. The surgeon looks into the urethra, bladder and vagina.
- Laparoscopy: This is a surgery using a small camera. The surgeon looks for the reproductive parts inside the body. The surgeon may also take small pieces of tissue.
How Do We Care for People with Differences of Sex Development?
The DSD team at Cincinnati Children’s includes doctors, nurses, psychologists, genetic counselors, child life specialists and social workers from several specialties:
Our team works together to provide care for people of all ages, from counseling before birth to treatment into young adulthood.
Treatment depends on the specific condition. Treatment and services may include:
- Diagnostic evaluation:
- Physical exam
- Blood tests
- Imaging (X-ray, ultrasound, MRI)
- Genetic counseling
- Psychosocial support
- Medical treatment
- Hormone therapy
- Procedures (as needed)
- Vaginal dilation
- Diagnostic procedures
- Surgery
