Figure 3. Fertility measurement of the first and second generation progeny mice.

The F1 female and F1 male mice that were obtained by embryonic transfer were bred with B6/C57J male and B6D2F1 female mice, respectively. Fertility was also checked by breeding F1 males and F1 females. During the testing period, the mice regularly produced normal-sized F2 generation litters at normal intervals. To determine the fertility of the second generation mice, F2 females were bred with F2 males. n =  number of breeding pairs used.