We report here on the precise ability of mouse androgenetic embryos produced by in-vitro fertilization of enucleated oocytes to develop to day 9.5 of gestation when cultured with M16 and CZB media. Androgenetic embryos cultured with CZB rather than M16 medium developed to the blastocyst stage in a more significant proportion (56.6% versus 45.0%, P < 0.001). However, after cavitation, the rate of cell proliferation of androgenetic embryos cultured with CZB medium was significantly decreased (P < 0.05). Embryo transfer experiments showed that blastocysts cultured with M16 medium were superior to those cultured with CZB medium in their ability to develop to 9.5-day-old fetuses (28.1% versus 11.1%, P < 0.001). These results showed that the present procedure for producing androgenetic mouse embryos is reliable and that M16 medium is superior for culturing the embryos. Fetal sexing by polymerase chain reaction (PCR) also demonstrated that both XX and XY embryos develop to 9.5-day fetuses at theoretical rates (1:2). This is the first finding that mouse XX androgenones survive after implantation.