SRD5A1 and SRD5A2 encode isoform 1 and 2 of 5α‐reductase that catalyzes the conversion of testosterone into the more potent androgen, dihydrotestosterone, and their protein products shared 50% sequence identity, but whether hemizygous deficiency each of them have similar effect in the development of hypospadias awaits future functional analysis. This evidence concerns the gene SRD5A1 and hypospadias.