Michael Zitzmann

1 INTRODUCTION Testosterone (T) is a natural hormone that is essential to maintain physical and emotional wellbeing in men, regardless of age. Male hypogonadism is an endocrine condition of testosterone deficiency with the potential to cause multiple morbidities and psychosocial complaints. The condition can be of primary (testicular), secondary (hypothalamic–pituitary) or so-called functional origin (as result of inflammatory conditions, obesity, or chronic illness).

1 INTRODUCTION Cryopreservation of human spermatozoa is the standard for preserving fertility in male cancer patients, those at risk of gonadotoxic therapy, patients with bladder neck obstruction, as well as men with severe oligozoospermia or ejaculatory disorders.1-5 Cryopreservation was first implemented in the 1960s for successful sperm storage and fertility preservation.6 A significant number of live births has been achieved using cryopreserved semen, facilitated by intracytoplasmic sperm...

1 INTRODUCTION Infertility is a condition defined by not achieving a clinical pregnancy after 12 months or more of regular unprotected sexual intercourse. Fertility problems affect about 10%−15% of couples of childbearing age. In about 30%−40% of infertile couples, the male partner is the major or sole cause of infertility.1 Partly, but not exclusively, male infertility is characterized by low sperm counts, reduced sperm motility, or a low percentage of spermatozoa with normal morphology.