The 46, XY disorders of sexual development are characterized by a 46, XY karyotype with or without the presence of Müllerian structures. It can be divided into disorders of testis development and disorders of androgen synthesis. The disorder of testis development includes gonadal agenesis and gonadal dysgenesis. The disorders of androgen synthesis are caused by mutations in the sterol delta-7-reductase gene. A mutation in the LH receptor causes lowering of testosterone, gonadotropin levels over follicle-stimulating hormone levels. Enzymatic defects in testosterone synthesis include congenital lipoid hyperplasia, P450 Side-chain Cleavage, 3β-hydroxysteroid dehydrogenase Type 2 deficiency, 17α-hydroxylase deficiency, P450c17 deficiency, 17β-HSD Type 3 deficiency and 5α-reductase Type 2 deficiency. Androgen insensitivity syndrome is due to the complete absence and impairment of androgen action. It can be diagnosed by genitogram, laparoscopy, surgical exploration and gonadal biopsy. Hormonal treatment may follow different pathways. Surgical therapy for female is feminizing genitoplasty and in male phalloplasty, scrotoplasty and distal urethroplasty etc.