Production of normal young following transfer of mouse embryos obtained by in vitro fertilization between cryopreserved gametes.

Unfertilized oocytes (C57BL/6N and C3H/He) and epididymal spermatozoa (DBA/2N and Jcl:ICR) from mice were frozen separately and stored at -196 degrees C. After thawing, in vitro fertilization was performed using C57BL/6N oocytes and DBA/2N spermatozoa, C57BL/6N oocytes and Jcl:ICR spermatozoa, C3H/He oocytes and DBA/2N spermatozoa, and C3H/He oocytes and Jcl:ICR spermatozoa. Embryos developed to the two-cell stage by incubation in vitro were transferred to the oviducts of female recipients on the first day of pseudopregnancy (day when vaginal plug was confirmed). The rate of development to two-cell embryos in each group was in the 22-45% range. When these two-cell embryos were all transferred to recipients, offspring were produced from 23-35% of the embryos.