Artificially induced gynogenesis is a major technique used for controlling the sex ratio of aquatic animals as well as for culturing selectively bred colonies. In this study, cryopreserved sperm of Japanese seabass was UV-irradiated and used to fertilize eggs of starry flounder and diploid gynogenesis was induced using cold and hydrostatic pressure shocks. Meanwhile, sperm but without cold or hydrostatic pressure shock were used as the haploid group; sperm were used for hybridization; and sperm were used as a control group. The results showed that cell division started at a similar point in time in the control group as in the gynogenetic haploids and hybridized embryos. However, as compared with the controls, embryonic development among each of the three experimental groups was retarded from the late blastula stage. All the hybridized embryos died before formation of an embryonic body; all the haploid embryos died before the heart started to beat. Thus, none of the embryos in these two groups could be successfully hatched. Embryonic development of a small portion of the gynogenetic diploids followed a pattern resembling that of the controls, although with less success: (58.01±5.30)% of embryos in the control group were hatched out at 100 h 10 min, with (35.11±6.19)% malformed; in comparison, only (0.11±0.01)% of the gynogenetic diploids were hatched out at 104 h 50 min, with (53.59±0.36)% malformed. Although the gynogenetic diploids had a very low hatching rate and a relatively high rate of malformation, we were still able to construct a gynogenetic colony of with normally developing larvae. Hence, we propose that this study uncovers a promising technique for gynogenesis, and the results provide abundant cytobiological evidence contributing to information on the developmental biology of haploid, hybridized, and gynogenetic embryos of this species.