There are numerous factors that can cause male infertility as a result of its effect on the generation and maturation of sperm in the testicles themselves, generating oligozoospermia (low concentration of sperm in semen), asthenozoospermia (low sperm mobility), teratozoospermia (alterations in sperm morphology) or secretory azoospermia (no sperm is produced in the testicles).
The most common causes of testicular male infertility include the following:
- High testicular temperature
- the normal temperature of the testicles should be between 35.5º and 36º. Any elevation above these figures has a negative impact on the sperm maturation process that begins in the seminiferous tubules.
- Toxic agent
- there are many environmental factors that can alter the activity of Sertoli cells, which play an essential role in spermatogenesis: tobacco, environmental contamination, pesticides, consumption of meat of animals hormoned with oestrogens, use of certain medications, radiotherapy, professional exposure to toxic substances, etc.
- Klinefelter syndrome or XXY males
- it is a chromosomal abnormality in which males have an additional X chromosome, which generates a decrease in testosterone that prevents the production of sperm (azoospermia). In addition, it causes anatomical alterations in the sexual organs, such as hypoganadism or micropenis.
- Other genetic factors
- genetic alterations have been detected in areas of the Y chromosome that affects that negatively affect the spermatogenesis process causing oligospermia or azoospermia. This is the reason why, in assisted reproduction clinics, men with a sperm concentration of less than five million are asked for a study of Y chromosome microdeletions.
- strong blows to the testicles can affect the production and maturation mechanisms of sperm.
- Testicular pathologies
- there are different diseases that affect the testicle and spermatogenesis:
- Varicocele: it is responsible for 20% of cases of male infertility that are detected in assisted reproduction clinics. It is characterized by venous valve insufficiency of the spermatic veins and, depending on its severity, can cause teratozoospermia and oligozoospermia.
- Cryptorchidism: it is a problem that occurs essentially in boys when one or two testicles do not descend into the scrotum, so, among other things, they are subjected to temperatures above 36º, which affects the quality of the sperm. It can also occur after puberty as a result of mumps.
- Hydrocele: it is the accumulation of fluid around the testicle, which causes a significant increase in the overall volume of the scrotal bag that contains it. In principle it may not compromise fertility, but there is risk that it can cause infertility.
- Genitourinary infections: they can produce testicular atrophy, obstructions of the seminal pathways, generation of anti- sperm antibodies or compromise the accessory glands. They account for 5% of cases of male infertility.