B Spermatocyte chromosomes that underwent condensation (right) within a MII oocyte (MII chromosome mass, left). In this study, spermatocytes picked up for injection had tetrad chromosomes ready for condensation. C Chromosomal analysis of MII oocytes that had been injected with primary spermatocytes. In the spermatocyte-injected groups, normality was improved by reducing the ooplasm mass (*P < 0.005 by Fisher's exact probability test). Arrows in the right figure indicate prematurely separated chromatids. The numbers of oocytes observed are indicated on the top of the bars. 