Endocrine disruption in sexual differentiation and puberty - What do pseudohermaphroditic polar bears have to do with the practice of pediatrics?

What do pseudohermaphroditic polar bears and girls with premature breast de velopment have in common? Hormones. Sexual differentiation and the initiati on of secondary sexual characteristics, such as breast growth, are both und er the control of the sex hormones estrogen and androgen. Abnormal differen tiation of the internal or external genitalia in bears and early onset of b reast development in girls also may have a con-anon element-exposure to env ironmental hormones.