Follicle-stimulating hormone, decreased
Less common causes
Sertoli-cell-only syndrome
Congenital adrenal hyperplasia
47/XXX aneuploidy
Klinefelter syndrome
Cryptorchidism
Turner syndrome
Myotonic dystrophy
Testicular torsion
Idiopathic premature ovarian failure
Incomplete androgen insensitivity
Uncommon causes
FSH receptor deficiency
5-alpha reductase deficiency
Galactose-1-phosphate uridyltransferase deficiency
Pharmacological causes
Clomiphene citrate
Tamoxifen citrate