CYP19A1 and ovarian hyperstimulation syndrome: Substantial advancements have been obtained with the diffusion of random start protocols (i.e., promptly initiating the ovarian hyperstimulation regardless of the menstrual phase), dual stimulation (performing two hyperstimulation cycles one after the other), the use of aromatase inhibitors in women with hormone-sensitive cancers (to lower peripheral levels of potentially detrimental hormones) and ovulation triggering with Gonadotropin Releasing Hormone (GnRH) agonists rather than human Chorionic Gonadotropin (hCG) (to prevent Ovarian Hyperstimulation syndrome—OHSS) [11–14].