Resumen

An atypical case of sexual development disorder, where the presence of an intersex evidenced in the physical examination, is described in a twin male bull of the Gyr breed. Initially, it was believed that the animal analyzed corresponded to a case of freemartins, having a feminine appearance. In addition, the physical examination of the animal evidenced several abnormalities, had feminized phenotype, smaller size, did not develop male gonads and had a highly developed clitoris in the form of the penis. However, the results of cytogenetic and molecular analysis suggest that the sexual disorder presented in the female is not a case of freemartins and that the female is actually a male who presented a case of intersex. Although in the macroscopic examination of the organs were observed rudiments of what could be vulva, uterine horns and ovaries; the histological evaluation does not show the presence of female cells in these tissues, but if a histological structure of the epididymis is observed. This is an unusual situation of disorders of sex development with genital tract anomalies in cattle, probably associated to a mutation in a gene involved in the proper development of the male gonad.