CYP17A1 and hypospadias: Moreover, three studies found that key enzymes involved in testosterone synthesis, represented by Cyp11a1, Cyp17a1, Hsd3b, Scarb1, Star, Hsd17b3 and Srd5α2, were significantly reduced at the genetic level in DBP- or DEHP-induced hypospadias male fetal rats (26, 31, 32).