IGF2 and obesity due to melanocortin 4 receptor deficiency: Based on previous findings reduced IGF2 contents in infertile female other than obesity was noticed (e.g., oocytes from patients with ovarian hyperstimulation syndrome and polycystic ovarian syndrome), perhaps adding IGF2 to culturing systems may have the potential to improve the revenue of embryos with better quality from these additional populations of women, which may also exert a positive impact on implantation as well as pregnancy rate.