The most accepted theory is that the testes were present during the first trimester of gestation—allowing normal male sexual differentiation—but were destroyed or reabsorbed later due to vascular accident.
Anorchidism (Anorchia): Causes, Diagnosis, and Management Anorchidism, commonly known as or "vanishing testis syndrome," is a rare congenital condition characterized by the absence of one (monorchidism) or both (bilateral anorchidism) testes at birth. While the external genitalia appear normal male, the testicular tissue is missing from the scrotum and inguinal canal.
Diagnosis is challenging because anorchia presents similarly to severe intra-abdominal cryptorchidism. Initial detection of empty scrotrum.
A common hypothesis is that the testis undergoes twisting (torsion) during fetal development, leading to ischemic necrosis (tissue death) and subsequent absorption of the tissue.
Absence of both testicles. This is rare, occurring in roughly 1 in 20,000 males. Causes and Etiology
Individuals with bilateral anorchia cannot produce sperm.