Abstract: A process is disclosed for separating and collecting viable female spermatozoa (XX chromosome) and male spermatozoa (XY chromosome). The process utilizes apparatus comprising two sterilized columns of glass, plastic or other suitable material, a ball valve, a vacuum pump, a mercury manometer, and connecting tubes of glass, plastic or other suitable materials. The system is assembled with rubber percussion gaskets or other suitable connecting materials, to prevent the introduction of extraneous air into the closed system, and a burp bottle to preclude unwanted introduction of fluids into parts of the system under vacuum. The column containing the semen sample may be of variable volume, to accommodate semen samples of varying volume and concentration.The process may be modified by introducing into the system a direct and continuous electrical current flow, or by creating within the separating columns an electrophoretic field.