Round Spermatid Injection

Round spermatid injection (ROSI) is a technique of assisted in-vitro fertilization (IVF). ROSI technique involves the injection of haploid germ cells that have completed meiosis derived from testicular biopsies into the recipient oocytes. In some infertile men (i.e., those with azoospermia), round spermatids are the most mature cells visible during testicular biopsy. Currently, human ROSI is considered a very inefficient procedure and of no clinical value. Despite the limitations of ROSI and diminished clinical success rates, the use of round spermatids for fertilization is still considered useful as a treatment modality for men with azoospermia, and attempts at optimization of the technique are still ongoing.