| abstract |
A method of controlling the sex of mammalian offspring by separating spermatozoa into fractions having the desired sex characteristics and artificially inseminating the female to produce offspring of the desired sex. The sperm is separated by applying a buoyant force or forces to a mixture of sperm in nutrient media so that separation occurs according to density of the sperm. The nutrient media is controlled as to density characteristics and can have a uniform density gradient from top to bottom so that buoyant forces within such media are selectively applied to sperm of different density to effect separation of the sperm and to hold sperm fractions of different density in suspended relation within the nutrient media. Substantially pure sperm fractions (having the desired male or female sex characteristics) are isolated at the top or at the bottom of a separation column for use in artificially inseminating the female. Under certain circumstances, separation of the sperm into fractions is enhanced by the application of gas pressure (positive or negative) above the mixture of sperm and nutrient media in the column. |