Abstract: A method for biasing sex selection, the method comprising the introduction into a uterus of a subject a volume of micro-particle conjugates (10), wherein the micro-particle conjugates are proportioned so as to approximate the size and shape of spermatozoa and thereby be carried by peristaltic waves through the uterus and fallopian tubes to the infundibulum, at which point any spermatozoa present or arriving thereafter undergo capacitation and expose antigens that may be bound by anti-male antibodies (14) provided in the micro-particle conjugates (10), the binding of the exposed antigens on the spermatozoa by the anti-male antibodies resulting in their inability to penetrate the Zona Pellucida of an egg and effect fertilisation.

Abstract: A method for influencing sex selection in artificial insemination, the method characterised by the exposure of unsexed semen to antibodies to sex specific antigens present on spermatozoa carrying chromosomes of an undesired sex, whereby the spermatozoa to which the sex specific antigens are bound are generally unable to effect fertilisation of an egg, such that fertilisation is likely to be effected by spermatozoa carrying chromosomes of a desired sex.