More cysts in mutant testes are in division than normal and 90% of these are in first prometaphase, metaphase I and anaphase I are rare, no second meiotic divisions are seen and spermatid cysts contain a maximum of 32 cells. Spermatid differentiation in these males is as advanced or more advanced as in "normal" X0 males.

Twice as many cysts are in division as normal in mutant testes, 90% of these are in first prometaphase. True second divisions are not seen and in accordance, the number of spermatid nuclei per cyst never exceeds 32. Tri- and sometimes tetrapolar spindles are found in all cysts, although their frequency, as well as spatial pattern of their poles, vary considerably. All three poles conform with asters, but only one of them coincides with either of the two ends of the elongated nucleus. Every diploid spermatid nucleus has two detached centrioles in its cytoplasm. The centriolar bodies look normal and undergo the same morphogenetic transformations as the attached normal centrioles. Micronuclei are relatively rare. The sperm heads are deformed and are found spread along the length of the tail bundle, never attached to the basal body end of the tails.