A recessive gene, silkless, makes the pistillate inflorescence of maize sterile, but does not affect the staminate inflorescence. Such plants are functionally males. Another recessive gene, tassel-seed, changes the terminal inflorescence from a pollen to a seed-bearing structure. These plants are functionally females. Crossing tassel-seed by silkless produced normal hermaphrodites. In later generations double recessive plants were obtained, indistinguishable in appearance from tassel-seed plants. These double recessive females when pollinated by males homozygous for silkless and heterozygous for tassel-seed produced progenies having male and female plants only, and the union of these two types is expected to give only male and female plants in following generations. In this way an hermaphroditic organism has been changed to a separate-sexed organism.