Efficiency of MicroSort flow cytometry for producing sperm populations enriched in X- or Y-chromosome haplotypes: a blind trial assessed by double and triple colour fluorescent in-situ hybridization.

Using fluorescent in-situ hybridization (FISH) we have evaluated, on a blind basis, the efficiency of flow cytometry to separate human X- and Y-chromosome bearing spermatozoa. Our data demonstrate that human spermatozoa can be sorted to a purity of 80-90% for X spermatozoa and of 60-70% for Y spermatozoa. Our results using triple FISH fully agree with the sorting treatment used in each case and corroborate the efficiency of the flow sorting technique for sperm sex selection. In these limited samples (200-500 sperm/donor), the frequencies of disomic or diploid spermatozoa were not increased when comparing the sorted samples with unselected samples or with our control series.