Since the use of testicular spermatozoa in programs of assisted fertilization proved very successful, attention was focussed on the use of spermatids also carrying 23 chromosomes. Several difficulties became obvious; the first one concerned the recognition of round spermatids. This is a problem which does not concern elongating and elongated cells. The intra-cytoplasmic injection of elongated spermatids resulted in several pregnancies but this is not so for the round ones. Although, in the group of patients in whom only round spermatids are found at the time of the attempt, is to be divided into two categories; patients in whom previous research allowed to find spermatozoa, however few, and patients who never produced spermatozoa at all. This last group is no longer an indication for intracytoplasmic sperm injection procedure unless in the future new culture media allow a maturation into elongated forms.