The female germinal fluid is unable to induce the differentiation of spermatids in vitro.

During the first 24 h of incubation, the percentages of step 1–3 spermatids, step 7–9 spermatids and spermatozoa are almost unchanged (P > 0.05). The spermatids degenerated after 24 h-incubation in the female germinal fluid; therefore, data are not obtainable at 36 h.