Melissa Gardner, Emilia Floody, & David E. Sandberg
March 2022

We have created an information resource guide for parents and family members to explore. This guide provides basic information about conditions that affect how your baby’s body looks or works and continues with more specifics about their condition and its management. Some specific topics include how you can share information with other people (including family, friends, and your child as he or she grows up) and whether you and your medical team may consider further testing (including genetic tests). Depending on your child’s specific condition and the healthcare team who takes care of your child, parents can be asked to help make treatment decisions. When that happens, we want you to know you are not alone. Your child’s medical team is there to help, and we are here to help by giving you information and helping you think carefully through different options. There are different sets of questions throughout this guide to help you.

Your child was born with a body that looks and works differently from other babies. This is because their sex development has been affected by one of many conditions, known as Differences of Sex Development (DSD). There are a lot of different words people use to describe these conditions. Some people will say “Disorder” of Sex Development. Others may say “Variation in Sex Characteristics (VSC)” or “Intersex.” Words like these are “umbrella terms” that can mean many different conditions. You may choose to use one term or another based on what you hear your child’s doctors use, or based on which you feel most comfortable with. Once you know the name of your child’s specific condition, you and your doctor will probably prefer to use that instead.

Babies can follow different sex development paths in the womb. Some paths are taken more often than others. All sex development paths lead to a combination of sex characteristics. These sex characteristics include, for example, sex chromosomes (X and Y) and how the genitals look. When sex development takes a less common path, a person can have a different combination of sex characteristics.

Most Boys Typically Have
• XY Chromosomes
• A penis
• Testes and no uterus
• A lot of testosterone and a little

Most Girls Typically Have
• XX Chromosomes
• A vagina and clitoris
• Ovaries and a uterus
• A little testosterone and a lot of

Variations of development

Sex development is a complex process and many combinations or variations are possible. Each of these variations can change the way your baby’s body looks or works. To clarify, sex development refers to the biological or physical sex characteristics of a person. These include the sex chromosomes, hormones, gonads (ovaries or testes), and genitals. These do not include gender or sexual orientation.

Why did my child take a different path?
There are many reasons why babies take different pathways in development. Sometimes, they involve genes. Genes are pieces of information in every cell of the body that serve as the instruction manual for how bodies develop. Changes in genes may sometimes cause unexpected combinations of sex characteristics to develop. They can also affect the way babies produce or respond to hormones. Sometimes, changes in genes are inherited from the biological parents. Other times, they occur randomly.

How common are these different paths?
Some paths are relatively rare. Others are quite common. Although the changes these paths cause in a body are already present before birth, they can go unnoticed for months or years. Not all of these changes lead to visible differences in how a body looks.

Are these paths life-threatening?
Most changes in a baby’s sex development do not affect general health, but some do. Children with one type of change may require different care than those who are affected by another type. That is why it is important to understand which condition (or “diagnosis”) your child has.

Why are there so many different names for these conditions?
Terms like DSD or Intersex are general terms covering lots of different conditions. Some of these conditions have very different effects on health, and doctors use different words to describe this. Some doctors use the word “disorders” instead of “differences” of sex development. This is because differences that cause a change in the way a body works are often referred to as disorders.

Some people don’t like the term “disorders” because it sounds like something is “wrong” with their child. Because of this, many people prefer the term Differences of Sex Development, or use the name of their child’s specific condition instead.

Klinefelter Syndrome/47xxy

What is it?
Children with Klinefelter Syndrome (KS) have one extra X chromosome in addition to their 46, XY chromosomes (written as 47, XXY). Some children have the extra X chromosome only in some cells, while their other cells have 46, XY chromosomes. This is called “mosaic” KS (written as 46, XY/47, XXY).
• Most children with KS physically develop like most other boys.
• The testes are of a small to typical size at birth, but they do not grow further and do not produce as much testosterone, especially later in puberty. The penis, therefore, usually remains small. In addition, fathering children is usually not possible without surgical help.
• Children with mosaic KS may have milder signs and symptoms, depending on how many cells have an extra X chromosome.
• Some boys and men experience social anxiety or difficulties with social communication and interaction with peers. Others have difficulties with speech, spelling, reading, writing, and attention.
• Some men with KS also have sparse facial and body hair and may have enlarged breasts (called gynecomastia). They are usually tall and have less muscular bodies and weaker bones.

What causes it?
• The chromosomal change usually occurs as a random event during the formation of reproductive cells (eggs and sperm) in a biological parent. For example, an egg or sperm cell may gain one or more extra copies of the X chromosome as a result of an error in cell division.
• KS and its variants are not inherited.
• Biological parents who have a child with KS have a 1 in 100 chance that they will have another child with the condition.
• KS is quite common and occurs in 1 out of 500-1000 live births.

Is my baby a boy or a girl?
• Most boys with KS grow up to be happy as men, even if they have atypical chromosomes or smaller testes.
• Some boys with KS prefer less typical boys’ activities and tend to be more quiet, shy, and sensitive than boys without KS.

What are the treatment options?
Support and Counseling
• Talking to a psychologist, counsellor, or other professionals can help you learn more about your baby’s body as they grow and develop.
• This can also help you become more familiar and comfortable with your baby’s condition and if or how you might choose to share information with others.
• As your child gets older, these same professionals can help you teach your child about their body and can help them answer questions they might have.
• Extra speech therapy can help improve speaking, reading, and writing skills.
• Counselors and therapists can also give boys and men practical skills to help them feel more confident in social settings.
• You might also want to talk with other parents of children with the same condition or adults who have it.
• You can look at the section “Support for Families” for more information about these resources.

Genital surgery
• Although uncommon, some boys with KS have “hypospadias.” If the hypospadias is more severe, it may cause urinary problems. In most children, however, atypical genitals, such as mild hypospadias or a small penis cause no medical problems and surgery is not medically necessary or urgent.
o “Hypospadias” means that the opening to the urethra is located somewhere other than the tip of the penis. It can be on the underside of the penis, at the base of the penis, or in the scrotum. This can happen in boys.
• Surgery to your child’s genitals in childhood may result in irreversible damage to sensitive nerves.
o This can lead to problems with sexual pleasure and sensation in adulthood.
o Surgical revisions are often necessary to correct complications from childhood surgeries, such as narrowing of the urinary tract or leaks.

Gonadal monitoring
• There is usually no increased risk of cancer in the testes in men with KS.

• Because the testes are small and produce little testosterone, extra testosterone treatment will help bring on the usual changes of puberty, including a deeper voice, growth of the penis, and facial and body hair.
o This hormone treatment is lifelong.
• Testosterone treatment may have additional benefits, including increased physical strength, improved bone density, and reduced breast growth.
o However, some men have a difficult time finding an appropriate hormone replacement without experiencing side effects.
• Testosterone therapy cannot increase the size of testes or help with fertility.
• Although breast cancer in men is uncommon, there is an increased risk of breast cancer in men with KS.
o Some men prefer to have cosmetic surgery to reduce their enlarged breasts.
• Physical therapy can build muscle strength and coordination.