Table 1.

Definitions of clinically relevant gonadotoxicity.

Females	Males
Menstrual cycle disorders Amenorrhea/oligomenorrhea Hormonal treatment: puberty induction/hormonal replacement therapy	Disorders of sperm quality Azoospermia Oligozoospermia
Hormone levels above the normal range Follicle-stimulating hormone (FSH) Luteinizing hormone (LH)	Hormone levels above the normal range Follicle-stimulating hormone (FSH) Luteinizing hormone (LH)
Premature ovarian insufficiency (POI) Oligo-/amenorrhea for at least 4 months and an elevated FSH level > 25 IU/L on two occasions at 4 weeks apart before the age of 40. (ESHRE Definition)	Gonadal dysfunction Low testosterone levels Hormonal treatment: testosterone therapy
Low ovarian reserve parameters Anti-Müllerian hormone (AMH) not detectable	Hormone levels below the normal range Inhibin B