Intersex is a group of conditions where there is a discrepancy between the external genitals and the internal genitals (the testes and ovaries).
The older term for this condition is hermaphroditism. Although the older terms are still included in this article for reference, they have been replaced by most experts, patients and families. Increasingly, this group of conditions is being called disorders of sex development (DSDs).
Disorders of sex development; DSDs; Pseudohermaphroditism; Hermaphroditism; Hermaphrodite
Intersex can be divided into 4 categories:
Each one is discussed in more detail below.
Note: In many children, the cause of intersex may remain undetermined, even with modern diagnostic techniques.
46, XX INTERSEX
The person has the chromosomes of a woman, the ovaries of a woman, but external (outside) genitals that appear male. This most often is the result of a female fetus having been exposed to excess male hormones before birth. The labia ("lips" or folds of skin of the external female genitals) fuse, and the clitoris enlarges to appear like a penis. In most cases, this person has a normal uterus and fallopian tubes. This condition is also called 46, XX with virilization. It used to be called female pseudohermaphroditism. There are several possible causes:
46, XY INTERSEX
The person has the chromosomes of a man, but the external genitals are incompletely formed, ambiguous, or clearly female. Internally, testes may be normal, malformed, or absent. This condition is also called 46, XY with undervirilization. It used to be called male pseudohermaphroditism. Formation of normal male external genitals depends on the appropriate balance between male and female hormones. Therefore, it requires the adequate production and function of male hormones. 46, XY intersex has many possible causes:
TRUE GONADAL INTERSEX
The person must have both ovarian and testicular tissue. This may be in the same gonad (an ovotestis), or the person might have 1 ovary and 1 testis. The person may have XX chromosomes, XY chromosomes, or both. The external genitals may be ambiguous or may appear to be female or male. This condition used to be called true hermaphroditism. In most people with true gonadal intersex, the underlying cause is unknown, although in some animal studies it has been linked to exposure to common agricultural pesticides.
COMPLEX OR UNDETERMINED INTERSEX DISORDERS OF SEXUAL DEVELOPMENT
Many chromosome configurations other than simple 46, XX or 46, XY can result in disorders of sex development. These include 45, XO (only one X chromosome), and 47, XXY, 47, XXX - both cases have an extra sex chromosome, either an X or a Y. These disorders do not result in a condition where there is discrepancy between internal and external genitalia. However, there may be problems with sex hormone levels, overall sexual development, and altered numbers of sex chromosomes.
The symptoms associated with intersex will depend on the underlying cause. They may include:
Ideally, a team of health care professionals with expertise in intersex should work together to understand and treat the child with intersex and support the family.
Parents should understand controversies and changes in treating intersex in recent years. In the past, the prevailing opinion was that it was generally best to assign a gender as quickly as possible. This was often based on the external genitals rather than the chromosomal gender. Parents were told to have no ambiguity in their minds as to the gender of the child. Prompt surgery was often recommended. Ovarian or testicular tissue from the other gender would be removed. In general, it was considered easier to reconstruct female genitalia than functioning male genitalia, so if the "correct" choice was not clear, the child was often assigned to be a girl.
More recently, the opinion of many experts has shifted. Greater respect for the complexities of female sexual functioning has led them to conclude that suboptimal female genitalia may not be inherently better than suboptimal male genitalia, even if the reconstruction is "easier." In addition, other factors may be more important in gender satisfaction than functioning external genitals. Chromosomal, neural, hormonal, psychological, and behavioral factors can all influence gender identity.
Many experts now urge delaying definitive surgery for as long as is healthy, and ideally involving the child in the gender decision.
Clearly, intersex is a complex issue, and its treatment has short- and long-term consequences. The best answer will depend on many factors, including the specific cause of the intersex. It is best to take the time to understand the issues before rushing into a decision. An intersex support group may help acquaint families with the latest research, and may provide a community of other families, children, and adult individuals who have faced the same issues.
Support groups are very important for families dealing with intersex.
Different support groups may differ in their thoughts regarding this very sensitive topic. Look for one that supports your thoughts and feelings on the topic.
The following organizations provide further information:
Please see information on the individual conditions. The prognosis depends on the specific cause of intersex. With understanding, support, and appropriate treatment, overall outlook is excellent.
If you notice that your child has unusual genitalia or sexual development, discuss this with your health care provider.
Diamond DA, Yu RN. Disorders of sexual development: etiology, evaluation, and medical management. In: Wein AJ, Kavoussi LR, Partin AW, Peters CA, eds. Campbell-Walsh Urology. 11th ed. Philadelphia, PA: Elsevier; 2016:chap 150.
Donohoue PA. Disorders of sex development. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 606.
Wherrett DK. Approach to the infant with a suspected disorder of sex development. Pediatr Clin North Am. 2015;62(4):983-999. PMID: 26210628 www.ncbi.nlm.nih.gov/pubmed/26210628.