Figure 1. Major pathways in sex steroid biosynthesis (progestogens in orange boxes, estrogens in yellow boxes, and androgens in blue boxes). CYP11A1=cholesterol desmolase, CYP17A1=17 alpha-hydroxylase/17,20 lyase, HSD3B=3 beta-hydroxysteroid dehydrogenase, HSD17B1=17 beta-hydroxysteroid dehydrogenase 1, CYP19A1=aromatase, SRD5A2=steroid-5-alpha-reductase, alpha polypeptide 2.