The spermatozoon is a sex cell, so it has half of the chromosomes (haploid). For this chromosome reduction to occur, meiosis must take place during spermatogenesis, that is, during the process of sperm formation.
The last stage of spermatogenesis is called spermiogenesis and is when the spermatozoa mature and are released and transported to the epididymis. This is where the mature sperm are stored until they are ejaculated. At this point, the sperm undergo a natural capacitation process as they pass through the female reproductive tract, which allows them to fertilize the egg after reaching it.
In the case of in vitro fertilization treatment, the sperm capacitation phase is carried out in the laboratory. There are two methods for this: density gradients and swim-up.
