Is there a future for spermatid injections?

Microinjection of spermatids into oocytes has proven to be a successful ass isted reproduction procedure in the animal model, In the human, low fertili zation and cleavage to the 4-cell stage were reported after intracytoplasmi c sperm injection (ICSI) with round spermatids. In comparison with a conven tional ICSI-testicular sperm extraction (TESE) programme, the implantation rate after round spermatid injection is dramatically low, Different problem s have been encountered during the development of the spermatid injection t echnique and they could be partially responsible for the lower outcome when using round spermatids. Compared with the round spermatid cells, spermatid s in the elongation phase are easy to isolate and identify from other round cells present in a wet preparation. The morphological identification does not reveal anything about the viability or the genetic normality of the rou nd spermatids. Severe testicular dysfunction may have consequences on the q uality of the few spermatogenic cells present, Others factors, such as the pathology of the patient, play an important role in the successful treatmen t. Even if the results are extremely low, spermatid injection seems more fa vourable for men who have already proven their capacity to produce some spe rmatozoa. A spermatogenic block at the round spermatid level has led to ear ly abortions, increasing the suspicion of the role of a genetic factor. In order for this technique to be safe for use in clinics, more intensive work is needed to improve the selection and handling of cells and to ascertain the genomic imprinting and gene expression necessary for embryonic developm ent, Hence, when using immature cells for conception, the screening of the patient and the follow-up of the pregnancies and babies should be mandatory .