Intersex people almost never have two fully functioning reproductive systems. Most have variations that blend or deviate from typical male or female anatomy.
What counts as intersex
Intersex is an umbrella for more than forty medical conditions that alter chromosomal, gonadal, or genital development. The term covers everything from 46,XX individuals with masculinized external genitalia to 46,XY people with a female appearance.
Chromosomes and the SRY gene
During the first weeks of pregnancy, an embryo is bipotential. Around week seven, the SRY gene on the Y chromosome directs the undifferentiated gonad to become a testis. If SRY is absent or misplaced, the gonad may develop as an ovary even in a person with an XY chromosome set.
Common intersex variations
- Complete androgen insensitivity syndrome (CAIS) – XY chromosomes, testes produce testosterone, but body tissues are unresponsive. The result is a female external appearance with internal testes.
- Congenital adrenal hyperplasia (CAH) – XX chromosomes, but excess adrenal androgens masculinize external genitalia.
- Ovotesticular difference of sex development (OT-DSD) – Both ovarian and testicular tissue may be present, but rarely both are fully functional.
Do any people have both functional systems?
In the rare OT‑DSD case, a person can have an ovary on one side and a testis on the other, or an ovotestis. However, the tissues usually do not work in parallel. A single body cannot support two complete, independent reproductive tracks; it lacks the resources and space to maintain both fully.
Hormones shape the outcome
Hormones act like builders. Even with the right genetic blueprint, if the body’s receptors are unresponsive—such as in CAIS—the hormones cannot direct development, leading to a different anatomical outcome.
How common is intersex?
Estimates vary. Some studies suggest about 1.7 % of births involve an intersex condition, while others count only about 0.018 % for conditions that visibly differ from typical male or female presentations. In either case, hundreds of thousands of people worldwide live with intersex traits.
Key takeaways
- Intersex is a spectrum, not a single disease.
- Most intersex people have one type of gonad, not both.
- Ovotesticular differences rarely produce fully functional male and female systems.
- Hormonal sensitivity is as important as chromosomal makeup.
- Intersex conditions are medically recognized and managed with care, not “fixed” by default.