How do reproductive organs change between birth and puberty?

Between birth and puberty, the human reproductive organs undergo a period of steady growth and gradual development of activity. While these organs are fully formed and in their adult positions at birth, they remain largely inactive during childhood.1

During this prepubertal phase, only small amounts of sex hormones circulate in the body. These low levels of hormones serve to inhibit the hypothalamus from producing the gonadotropin-releasing factors that would otherwise trigger sexual maturation.2

The transition to puberty begins when the hypothalamic cells become less sensitive to these circulating sex hormones. This change allows the pituitary gland to release gonadotropins, which in turn stimulate the testes to produce testosterone or the ovaries to produce estrogen. This hormonal shift marks the onset of rapid development in the reproductive organs and the emergence of secondary sexual characteristics.213