Changes in females
These changes begin to occur between the ages of 10 and 14 years. The hormones oestrogen and progesterone are responsible for them.
- Hair grows in the armpits, the groin and around the reproductive organs.
- The hips broaden.
- The mammary glands develop.
- Fat is deposited under the skin and the body becomes rounded.
- The growth of bones and muscles becomes rapid and the body grows larger.
- The release of ova from the ovaries — the menstrual cycle — begins.
The same pattern, and one difference
As in males, only the last item is reproduction itself. The difference is that where sperm production, once started, simply continues, the release of ova is cyclic — roughly one every 28 days. That cycle is important enough to have a section of its own later in this chapter.
Earlier, and by different hormones
Two things differ between the lists: females typically begin about three years earlier than males, and the changes are driven by two hormones rather than one. Everything else — the hair, the rapid bone and muscle growth, the body enlarging — is common to both.