RESUMEN
<p><b>OBJECTIVE</b>To analyze the sex chromosome meiotic segregation in inv(Y) patients by fluorescence in situ hybridization (FISH).</p><p><b>METHODS</b>Conventional cytogenetic procedures (GTG and CBG banding) and FISH were performed on metaphase chromosome. Three-color FISH was performed on sperm samples using a probe mixture containing CEPX, Tel Xp/Yp and Tel Xq/Yq to investigate the sex chromosome segregation of five inv(Y) (p11.1q11.2) carriers. A healthy man with normal semen parameters was used as control.</p><p><b>RESULTS</b>There was no statistical difference in the abnormal sex chromosome number and recombination frequencies in each spermatozoon from the patient in comparison with that in the control.</p><p><b>CONCLUSION</b>There was no apparent sex chromosome abnormality in the sperm of the inv(Y) (p11.1q11.2) carriers. Sperm-FISH allows further understanding of the sex chromosome segregation pattern and an accurate genetic counseling.</p>