The technique of In Vitro Fertilization by Intracytoplasmic Sperm Injection (IVF-ICSI) consists of the fertilization of the egg by injecting a single sperm into the cytoplasm of each mature egg. The selection of the spermatozoon to be injected is carried out by the embryologist himself, taking into account morphological and mobility criteria.
In contrast, the PICSI technique, also called physiological ICSI, allows the selection of spermatozoa according to their attachment to a molecule similar to hyaluronic acid. Therefore, in this case, it is not the embryologist who performs the sperm selection. Only mature spermatozoa, and therefore those with the greatest capacity to fertilize the egg, will join these molecules.