3.3 Million Intersex In United States
⚠️ Use discretion. Graphic human anatomy images.
A small number of human anatomy posters and models on this website depict average male genitals and female genitalia. Real-world differences reveal significant variance. About 1% of U.S. infants are born with atypical sex organs.  (Worldwide, the ratio can be as high as 2%.) Among an auditorium of 2,000 U.S. citizens, 20 were born with “ambiguous genitalia.” Two of those had gender “normalizing” surgery shortly after birth.*
An individual with ambiguous genitalia (hermaphrodite misnomer, now termed Ovotestis) falls within the larger category of intersex, estimated to comprise nearly 3.3 million persons in the United States. Sometimes the term Variations in Sex Characteristics (VSC) is used, as is Disorders of Sex Development or Diverse Sex Development (DSD). [2–3]
Intersex Classifications [3–4]
- Externally female with mostly male internal anatomy.
- Girl (XX) born with a macroclitoris (clitoromegaly).
- Boy (XY) born with a micropenis.
- Girl (XX) born without a vaginal opening.
- Boy (XY) born with divided labia-like scrotum.
- Child born with mosaic genetics, so that some cells have XX chromosomes and others have XY.
Infantile Testicular Hydrocele
At birth, each male testicle normally descends within its own fluid-filled sac. More commonly among premature births, the sac does not seal completely. This results in fluid accumulation outside of the sac called a communicating hydrocele. A noncommunicating hydrocele occurs when the sac surrounding the testicle closes, but the fluid is not absorbed. [5,6]
The hydrocele scrotum is disproportionately large in comparison to the penis. In rare cases, similar fluid collections can develop in females along the canal of Nuck—an abnormal open pouch of peritoneum extending into the labia majora. Most (80%) of congenital hydroceles resolve spontaneously before 2 years of age. [7,8]
A hydrocele can occur in adults as a result of syphilis, tuberculosis of the epididymis, the tropical disease caused by threadlike parasites called filarial worms (filariasis), cancer, or because of an injury. If a hydrocele does not resolve itself, a surgery called hydrocelectomy may be necessary.
Puberty is when gender differences become most apparent, and sometimes when ambiguity is manifest. However, some people with intersex anatomy live a full life without anyone (including themselves) ever knowing about their atypical internal anatomy. External organs may be unambiguous but not match the anatomy inside, contributing to the vast intersex community.  There is significant variance of mature sexual organs.
Female Genitalia Variation Table
|Clitoral length||5–35 mm||0.2–1.4|
|Clitoral glans width||3–10 mm||0.1–0.4|
|Clitoris to urethra||16–45 mm||0.6–1.8|
|Labia majora length||70–120 mm||2.8–4.7|
|Labia minora length||20–100 mm||0.8–4.0|
|Labia minora width||7–50 mm||0.3–2.0|
|Perineum length||15–55 mm||0.6–2.2|
|Vaginal length||65–125 mm||2.6–4.9|
Unassigned children might delay having appropriate surgeries until their teenage years or adulthood. By then, they may have already identified with a gender that differs from what matures during puberty. Hairstyles, makeup, and attire can sometimes mask gender. The adolescents do not have to be homosexual, though many forgo surgical assignment and identify as non-binary, intersex, androgynous, bisexual, or LGBTQ+. They may explore polyamorous or polyamory relationships. The absence of gender identity often leads to bullying and emotional issues. Anxiety and depression in sexual minority individuals appears to be more than double those of their heterosexual counterparts. [9,10]
Women with Swyer syndrome (ratio 1:80000) are born with XY (male) chromosomal makeup. Because of the high risk of cancer developing in non-functional streak gonads, surgical removal of male organs is commonly recommended. People with Swyer syndrome have minimal breast development. They don’t go through typical puberty, or experience menarche. So, without intervention, they are infertile. Because they do not have functional ovaries, affected individuals usually start a hormone replacement therapy during adolescence to induce menstruation and development of female secondary sex characteristics such as breast enlargement and uterine growth. 
Swyer syndrome causes women to be much taller and broader than their peers, with large hands and feet. On a basic genetic level, they are male. But since the condition is rarely diagnosed before the teen years, most identify as female even after diagnosis. Revealing to a mate the genetic inconsistency can cause anxiety because there is a fear of rejection. 
Vaginal agenesis is a rare in utero disorder that occurs when the vagina doesn't develop, and the womb (uterus) may only develop partially, if at all. It can appear as a small pouch or dimple where the vagina should be. Many girls with vaginal agenesis decide after puberty begins to have doctors create a vagina (pocket) by means of a vaginal dilator. Though infertile, orgasmic function is possible since the clitoris and the external genitalia form normally. 
Hypospadias occurs when the urinary opening (urethra) is located below the usual position on the tip of the penis. It is one of the more frequent and visible genital variations. Hypospadias is the most common birth difference in children with XY chromosomes, seen in 1 out of 300 live births. 
Intersex Sports Athletes
Intersex competition has upset Olympic sports since the 1930s. In the 1936 games, British female shot putter and javelin thrower Mary Louise Edith Weston and the Czechoslovakian female runner Zdenka Koubkova had each been born with dual biological sex traits. Later, they both surgically transitioned to men. This sparked popular biological gender testing in competitive sports. 
Today, Caster Semenya, the South African middle-distance champion, and Dutee Chand, the Indian sprinter are intersex athletes competing without surgical alteration. They are barred from certain competitions. Annet Negesa of Uganda identifies as female. She was born with both external female genitalia and internal male gonads that produce levels of testosterone equivalent to men. Negesa had a gonadectomy to continue racing against women, but the reduction of testosterone derailed her sports success. 
Who Decides Gender?
Now imagine your obstetrics doctor has delivered the 99th baby at the hospital in which you are admitted. Your child is number 100—the approximate ratio for intersex births. In the delivery room, there is a delay in the announcement that you are now a proud parent of the healthy baby boy you expect. Nurses whisk the infant away for a few snips and stitches.
Controversially, many doctors decide the gender of intersex infants based on published Prader stages and medical tests without the parents’ knowledge. If the child has a Y chromosome and an adequate or “reconstructable” penis, the child is assigned a male gender. Full-term newborns must have penises of 1 inch (2.5 cm) or larger to be assigned the male gender. [16–19]
If the child has no Y chromosome, it is assigned the female gender. If the child has a Y chromosome and an inadequate or “unreconstructable” penis according to doctors, the child is likewise assigned a female gender and surgically “reconstructed” as such. Surgeons alter the genitals to resemble what doctors think female genitals should look like. This may include clitoral reduction surgery and construction of a vaginal opening.
The gender criteria seems pretty scientific but there are occasional anomalies in the chromosomes. Humans are born with 46 chromosomes in 23 pairs. Most women are 46XX and most men are 46XY. Research suggests, however, that in a few births per thousand some individuals will be born as sex monosomies with a single sex chromosome (45X or 45Y). Others are born as sex polysomies with three or more sex chromosomes (47XXX, 47XYY or 47XXY, etc.). Some males are born 46XX. Females are also born 46XY due to mutations in the Y chromosome. Hence, there are not only females who are XX and males who are XY, but rather, there is a range of chromosome complements, hormone balances, and phenotypic variations that determine sex, concludes the World Health Organization. [19,20]
Human Genitals Anatomy Posters and Models
You anticipate a baby boy. When the doctor finally arrives in your hospital room with your newborn baby girl, there is some confusion but you are happy to hold her. Nurses assure you that this is your baby. What happens later during puberty? Doctors can prescribe hormones to direct female development. Later, as an adult, your “daughter” may be unable to conceive. For these and other reasons, organizations like InterACT recommend leaving infants unaltered at birth.
As a parent, do you feel that you should share in the discussion of gender assignment right after birth? In Canada, parents of one intersex infant were brought into a room of 30 intimidating medical specialists. They offered opinions before a urologist adamantly pressed for female assignment surgery. A social worker cautioned against sharing this secret with siblings. Some parents opt for gender X on their child’s birth certificate. About 7,000 intersex adults have gender-X IDs. [21,22]
Social and biological considerations complicate early Variations in Sex Characteristics (VSC) determinations. It can spoil plans for a gender-reveal party. Bianca Karvunidis, the very first gender-reveal baby girl, is now more comfortable wearing androgynous suits. Her mother regrets beginning the popular trend in 2008. 
Eric and Stephani have been talking to their child Rosie about her dual-biologic condition for years, but she is only beginning to understand that her body differs from the other children in her kindergarten class. Her parents frame the discussion in the context that all bodies are different. Not yet reaching puberty, so far Rosie has no concerns over her genetic differences. 
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*Estimated statistics vary due to unreported cases and geographic prevalence. Australia reports 1.7% of all live births as intersex. 
- How common is intersex? isna.org
- What is intersex? isna.org
- What is Ambiguous (Uncertain) Genitalia? urologyhealth.org
- Differences in sex development. nhs.uk
- Hydrocele Symptoms and Causes. mayoclinic.org
- Patil V, Shetty SM, Das S. Common and Uncommon Presentation of Fluid within the Scrotal Spaces. Ultrasound Int Open. 2015;1(2):E34-E40. doi:10.1055/s-0035-1555919
- Kono R, Terasaki H, Murakami N, Tanaka M, Takeda J, Abe T. Hydrocele of the canal of Nuck: a case report with magnetic resonance hydrography findings. Surg Case Rep. 2015;1:86. Published 2015 Sep 22. doi:10.1186/s40792-015-0086-5
- Huzaifa M, Moreno MA. Hydrocele. [Updated 2020 Jul 6]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK559125/
- What puberty is like as an intersex person. helloclue.com
- Anxiety and Depression in Sexual and Gender Minority Individuals. adaa.org
- Swyer syndrome. nih.gov
- Vaginal Agenesis Diagnosis & Treatment. childrenshospital.org
- Intersex Definitions. interactadvocates.org
- In the 1930s, intersex athletes worried Olympic officials about the future of women’s sports. timeline.com
- This Intersex Runner Had Surgery to Compete. It Has Not Gone Well. nytimes.com
- Clitoromegaly in Childhood and Adolescence: Behind One Clinical Sign, a Clinical Sea. karger.com
- What to know about micropenis. medicalnewstoday.com
- Sex determination – it can get complicated! 2010 PDF, infantjournal.co.uk
- Ogilvy-Stuart AL, Brain CE Early assessment of ambiguous genitalia. Archives of Disease in Childhood 2004;89:401-407.
- Gender and Genetics. who.int
- More than 7,000 Americans have gender X IDs, a victory for transgender rights. Is it a safety risk, too? usatoday.com
- Legal recognition of non-binary gender. wikipedia.org
- Here’s Why You Shouldn’t Throw a Gender Reveal Party. medium.com
- Intersex: When a baby isn’t quite boy or girl. todaysparent.com
- Intersex population figures. ihra.org.au
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