Changing sex hormone levels during the first 20 years of human life-history. Life-history stages of boys and girls (upper panel) may be defined by sex hormone levels (lower panel). Note the rise in sex hormones in early infancy – the so-called “mini-puberty”. Childhood is characterized by quiescence of sex hormones, followed by a juvenile increase of adrenal androgens and adolescent increase in gonadotropin and gonadal sex hormones, manifesting as puberty.