EFO_1001422 (Sertoli Cell-Only Syndrome) is a type of male infertility in which no germ cells are visible in any of the biopsied SEMINIFEROUS TUBULES (type I) or in which germ cells are present in a minority of tubules (type II). Clinical features include AZOOSPERMIA, normal VIRILIZATION, and normal chromosomal complement. Also known as: spermatogenic failure, x-linked, 1, x-linked spermatogenic failture type 1.