**Anorchia happens when both testicles form early in fetal development and are then lost before birth, most often because their blood supply twists shut.**
Doctors often call this vanishing testes syndrome. The early testes worked long enough to build male genitals and internal anatomy, so the loss usually happened later in pregnancy rather than at conception. A smaller number of cases trace to genetic changes that affect how the testes form, and rarely the condition runs in a family. Nothing a parent ate, took, or did in pregnancy is known to cause it. Confirming anorchia takes hormone blood tests, chromosome testing, and imaging, because an undescended testicle hiding in the abdomen looks the same from the outside.
How anorchia is managed
Common questions
Why does Anorchia happen?
Anorchia, also called vanishing testes syndrome, means both testicles are absent in a person with XY chromosomes. The testes almost always formed and worked early in pregnancy, since male genitals developed, and were then lost later, usually when the cord of blood vessels supplying them twisted and cut off circulation. Genetic changes affecting testicular development explain a small share of cases. It is not caused by anything a parent did while pregnant. Because an undescended testicle can look identical from the outside, diagnosis needs hormone blood tests, chromosome testing, imaging, and sometimes surgery to confirm no testicular tissue remains.