Abstract
Intracytoplasmic sperm injection (ICSI) has been performed to the treatment method of for male infertility. Using ICSI, in the mouse or other species, round spermatid injection (ROSI) has been successful, however, its application in human is controversial. To obtain much information on round spermatids, culture of round spermatids under in vitro conditions is an effective method. Mouse round spermatids cultured in the presence of recombinant FSH and testosterone show normal differentiation into elongating spermatids, and the elongated spermatids show normal oocyte activation and fertilization.
