A method of producing at least one undifferentiated cell comprising uniting two haploid cells to form a diploid single cell under conditions to support fertilization in a gravity condition or environment under normal earth gravity, after unification is complete, preserving the resulting diploid single cell so that no replication of the diploid single cell occurs, reviving the diploid single cell under a weightless condition or environment, and culturing the diploid single cell in culture medium in a weightless condition or environment to obtain replication of the diploid single cell that will not develop into an embryo of differentiated cells and tissue.