Induction of somatic haploidization by the mature oocyte in mice. The G0/G1 somatic cell was transferred into the enucleated MII oocyte and the somatic cell-derived spindle was reconstructed. During the resting time after SCNT and fertilization, various chemicals and proteins, such as fasudil, retinoic acid (RA), and RAD51-Stimulatory Compound 1 (RS-1), were treated. Fertilization induced the extrusion of the pseudo-polar body (PPB) and the formation of two pronuclei, one from the somatic nucleus and the other from sperm. Somatic homologous chromosomes were segregated into PPB and somatic haploid embryos. The somatic haploid embryos can develop into blastocysts and produce live offspring.