This article states a hypothesis of devising a new, immune-contraceptive vaccine against sperms. Experimental research has already been carried out in this area, using antigens from the sperm head. This poses several problems like acrosomal interference and variations caused due to capacitation of the sperm. We have suggested that the SPAG6 antigen on the sperm tail be used for the same purpose, which will overcome all such troubles and maintain a uniformity of interaction in the recipient female. This vaccine, when formulated, can be used to immunize females who use a convenient and non-invasive birth control method.