This study examined the feasibility of isolating and transferring the centrosome-containing region of spermatozoa to mature human oocytes. The findings demonstrate that individual sperm centrosomes can be transferred and are capable of nucleating maternal tubulin to form a well-developed sperm aster in the recipient oocyte. The results are discussed with respect to centrosome function in early human development and applications in clinical in-vitro fertilization in the treatment of certain forms of male factor infertility.