Abstract
Mouse haploid and diploid parthenogenetic embryos were cultured in 25 μl of Whitten's medium using 1, 5, 10 or 20 embryos. Improvement in development was observed at higher embryo densities. Development of haploid parthenogenetic embryos was improved in terms of both the percentage of blastocysts and the number of cells per blastocyst. In diploid parthenoge-netic embryos, an increase in the number of cells per blastocyst was observed. These results demonstrate that the development of parthenogenetic embryos is affected by embryo density. In vitro culture of 10-20 parthenogenetic embryos together can enhance their preimplantation development.