Possibly reversible conditions (e.g., varicocele, obstructive azoospermia)

Conditions that are not reversible but in which viable sperm are available (e.g., inoperable obstructive azoospermia, ejaculatory dysfunction)

Conditions that are not reversible and in which there are inadequate or no viable sperm available (e.g., hypogonadism)

Serious, potentially life-threatening conditions (e.g., testicular cancer, pituitary cancer)

Genetic abnormalities that affect fertility (e.g., cystic fibrosis gene mutations associated with absence of the vas deferens, chromosome abnormalities resulting in impaired testicular function)