Male infertility is defined as the inability of a man to father a child. Although male infertility may be associated with impotence, many infertile men have perfectly normal and happy sexual relationships.
Male infertility can be classified into four main types:
- No sperm (azoospermia) accounts for 2% of male infertility.
- Poor sperm quantity (oligospermia) or quality e.g. low motility (asthenozoospermia) or a high percentage of abnormal sperm (teratozoospermia). Antisperm antibodies, etc. This subgroup may account for about 50% of male infertility.
- Sperm dysfunction, where there is a normal semen analysis but the sperm lack or have a defective fertilizing capacity, resulting in complete failure of fertilization or poor fertilization of the eggs in IVF. This may account for 45% of male infertility.
- Inability to ejaculate into the vagina. This accounts for 3% of male infertility.