In 2016, ovarian stimulation faces two main challenges: how to obtain good quality oocytes while not endangering the patients treated, but also limited by maternal age and poor ovarian responders (POR). The first IVF birth, Louise Brown, was obtained from a natural cycle. With the introduction, in the 1980s of gonadotropin releasing hormone agonists (GnRHa) and in the 2000s of GnRH antagonists (GnRHant), stimulation became plurifollicular (and source of consequences). Today, only about 50% of the transferred blastocysts after IVF lead to a pregnancy. The purpose of this review was to describe the current challenges and limits of ovarian stimulation.