When a male presents a low quantity of spermatozoa in the ejaculate, it may be due to a testicular cause, that is, a problem in the testicles.
- Cryptorchidism or incomplete descent of the testicles.
- Varicocele or dilatation of the veins of the spermatic cord.
- Hydrocele or accumulation of fluid in the testicle.
It should be noted that these are not the only testicular causes of oligozoospermia; some genetic alterations can also alter testicular function.