The fact that parenthood is postponed increasingly more time has led the British Dr. Kevin Smith to state that men should have their sperm frozen at 18 years of age for use at a later date, with age the chances of having a child with certain disorders increases.

Endometriosis is a disease that affects 1 in 10 women of childbearing age. Painful periods and infertility are the main symptoms that can lead to this diagnosis, and other more specific tests such as biopsy. Although endometriosis can be a symptom of infertility, only 20-30% of women suffering from endometriosis have difficulty getting pregnant.

Early cleavage, understood as the first embryo mitosis at 25–27 hours after insemination, has been considered to be an embryo quality parameter (1–9).