According to this system female is homogametic or XX and male has X chromosome and not Y. Females produce the same type of egg (X) and males produce two types of sperm (X and A). When a woman’s egg X meets a man’s sperm X, a female child (XX) will be produced. Again, the union of the woman’s egg X with the man’s sperm A will produce a son (XA). This method determines the sex of animals like grasshoppers, beetles, Orthoptera, Heteroptera, Dioscorea (plants).