Deterioration of sexual development is one of the actual problems, namely, the difficulty of its diagnosis, because there is no universal Protocol that would be recommended for all cases of sexual dysfunction. An important problem is that there is a considerable number of diagnostic methods, but the specificity and effectiveness vary in a wide range. Diagnostic laparoscopy and genetic testing, including chromosomal analysis, comparative genomic hybridization (CGH), FISH to determine SRY, are among the most effective diagnostic methods that can be used to verify pathology that may not be detected by routine methods. Timely diagnosis is extremely important due to the fact that the sooner the violation is verified, the sooner the correct gender is delivered to the patient and the appropriate correction is made for him. It must be remembered that patients with impaired sex formation have the risk of malignancy of the gonads. This article presents a clinical case of diagnosis and management of a patient with impaired sexual development at the age of 1 year and 6 months, showing how important a comprehensive diagnostic examination is, as well as diagnostic methods for making a correct diagnosis.