The abnormal development of gonads which means that the sex hormones are not being produced. The gonads are the primary reproductive organs - testes in males and ovaries in females. These organs produced sperm and eggs as well as sex hormones - testes produce the male hormone called testosterone and ovaries produce the female hormone called estrogen. Abnormal gonad development and hence lack of sex hormones can affect sexual differentiation between males and females and puberty may be delayed or fail to occur altogether. See also Gonadal dysgenesis