LAUSR

RESEARCH QUESTION Do spermatozoa with different sex chromosome complements (X and Y; aneuploidy and monosomy) exhibit different degrees of DNA damage? DESIGN A prospective, observational study to measure the DNA fragmentation level and sex chromosome complement simultaneously using combined sperm chromosome dispersion (SCD) and fluorescence in-situ hybridization tests. Two methods were used to evaluate SCD images: a traditional semi-quantitative method to categorize halo size and a newly developed quantitative method based on the Matlab image analysis programme to more precisely measure the halo area and calculate the halo size index (HSI). RESULTS The HSI (which was inversely proportional to DNA fragmentation level) of Y chromosome-bearing spermatozoa was significantly (P < 0.05) lower than that of X chromosome-bearing spermatozoa in both normozoospermic and pathozoospermic groups. The HSI of sex chromosome-aneuploid spermatozoa was also significantly (P < 0.05) lower than that of monosomic spermatozoa. CONCLUSIONS Our results indicated that Y chromosome-bearing spermatozoa are more susceptible to DNA damage than X chromosome-bearing spermatozoa, and the segregation errors during the meiotic division of spermatogenesis (resulting in aneuploidy) constitute an important contributory cause of DNA damage.