A direct cytogenetic technique for assessing the rate of first meiotic non-disjunction in the human male by the analysis of cells at metaphase II.

The successful application of a triple staining technique incorporating quinacrine mustard fluorescence, lacto-propionic orcein staining and C-banding to metaphase II cells in the human male is described. This procedure overcomes the major technical difficulties associated with the analysis of these cells, enables unambiguous chromosome counts to be made and allows the majority of cells to be karyotyped. Preliminary results on two hundred cells from six men with apparently normal karyotypes are presented.