Abstract: The present invention is a method for sex determination in ratites, such as ostriches. The method includes the steps of administering a material that causes sex to be determined to a fertilized ratite egg and incubating the egg until it hatches. Preferably, the administering step includes the step of injecting the material into the egg and preferably before the injecting step, there is the step of drilling a hole into the eggshell of the egg. The material that determines sex in ratites includes natural estrogens or a functionally equivalent amount of its synthetic mimics to cause female development and natural nonaromatizable androgens or a functionally equivalent amount of its synthetic mimics to cause male development. Preferably, the material is estradiol-17beta (for female development) or dihydrotestosterone (for male development). A solution may, for example, be comprised of 1.2 milligrams of estradiol-17beta preferably dissolved in 40 microliters of 95% ethanol, or 7.

Abstract: A method for sex reversal in reptiles and their derivatives comprising the steps of sterilizing the surface of a fertilized egg; injecting the egg with a material that causes sex reversal at least before the first two-thirds of incubation of the egg has passed; and sealing any holes in the egg. In a preferred embodiment, the material that causes sex reversal includes natural estrogens or its synthetic mimics. In an alternative embodiment, the material is applied to the surface of the egg. By practicing the aforesaid method, sex reversal in reptiles and their derivatives is accomplished and viable all female sexed hatchlings are capable of being produced thereby.