The determination of sex from forcibly removed hairs.

The determination of sex from forcibly removed hairs in forensic science laboratories has, in the past, been based almost entirely on the presence or absence of the Y chromosome in the cells of the hair root sheath. Since the human male genotype is XY and the female is XX, a technique was devised that permits root sheath cells to be stained sequentially for the Y and then the X chromosome using quinacrine mustard. Following staining, the Y and the X chromosome fluorescence were observed, at pH 5.5 and 3.0, respectively, by epifluorescence. The X and Y chromosome counts obtained for a single hair root specimen were reported as a Y-X (Y minus X) score. The results reported show that specimens from males gave positive Y-X score while specimens from females gave negative Y-X scores. Results of an age study and blind trials were also reported.