Sexual evolution plays an important role in the adaptation to their environment for organisms. Sexual differentiation is the basis on which creatures exchange their genes. Furthermore, what is the extra value of sex to their struggle for life in animals? Comparison of all-female Cnemidophorus with normal ones shows some element of sex that might not be previously considered. The mechanisms responsible for sexual behaviors of those lizards are largely unique. This paper reviews the fundament basis controlling pseudocopulation of all female lizards, which concerns genetic, endocrine and expression of sex hormone receptor genes in the brain.
