Molecular genetic characterization of mutations in SRD5A2 gene is used as an essential procedure for the final diagnosis of 5alpha-reductase deficiency. Here, we report a novel homozygous point mutation of SRD5A2 gene at codon 65 in exon 1, due to a proline for alanine substitution in a Turkish family whose proband has severe undervirilization. This mutation has not been reported up to date in association with 5alpha-reductase deficiency in various ethnic groups. We discussed some questions about gender assignment in addition to the molecular and clinical characteristics of the disease.