Fluorescent Y-chromosomes in hairs and blood stains.

Y-chromosome detection by way of fluorescence microscopy in biological materials has made sex determination possible in various areas of investigation. The present report describes the results of sex determination on hairs and blood stains. Significant differences were found between the Y-body count for female and male materials. In blind trials it was demonstrated that a reliable sex determination of hairs was possible for at least 27 weeks and of blood stains on cotton cloth and glass for 6 weeks. There were no false positive findings, but there was one male with a "female" blood smear count, who revealed an abnormally small fluorescent region on his Y-chromosome. The existence of such variants calls for caution when evaluating a low count.