[Advances in microinsemination with spermatid].

Men with non-obstructive azoospermia(NOA) can now be treated by using intra-oocyte round spermatid injection(ROSI) or elongated spermatid injection(ELSI). Spermatids can be retrieved from semen or from testis biopsy specimens. But the rates of fertilization and pregnancy with spermatids have been disappointing. Many problems limiting success rate and hindering a wide application of this technique still remain unresolved, including the incomplete maturation of spermatid nuclear, oocyte activation and identification of a live spermatid.