Puberty is the transition from boy to man or girl to woman and is characterised by the development of pubic hair in both sexes; the enlargement of the penis, scrotum and testes and the development of a beard in men; or enlargement of the vulva (opening lips of the vagina), fat deposition on the hips, development of breasts and the start of menstrual periods in women. After puberty a man and woman can create new life with a child, whereas before they cannot.
Many of the causes of delayed puberty apply to both sexes while others are sex specific. The onset of puberty is triggered by the hypothalamus (part of the brain) sending nerve signals to the pituitary gland, which lies in the centre of the head underneath the brain. This gland controls every other gland in the body, including the ovaries and testes, by sending chemical messages (hormones) to them through the blood stream.
When the testes and ovaries receive the appropriate hormonal signals from the pituitary gland, they in turn start to produce the sex hormones testosterone and oestrogen, which are responsible for the development of normal sexual characteristics. A tumour, cyst, cancer, abscess, infection or damage to the blood supply of the hypothalamus or pituitary gland may adversely affect these organs and therefore prevent the start of puberty. Irradiation to the brain and cytotoxic drugs to treat cancer will have a similar effect. A significant long term illness, persistent major infection, regular extremely vigorous exercise, cancer, malnutrition or serious emotional stress will affect the body’s functions generally, including the production of sex hormones.
Other causes of a delayed onset of puberty that may occur in both sexes include:
- hypothyroidism (an underactive thyroid gland), a serious infection that involves both ovaries or both testes,
- Addison’s disease (under active adrenal glands),
- Noonan syndrome,
- Laurence-Moon-Biedl syndrome (inherited condition that causes night blindness, intellectual disability, obesity, small genitals and sometimes extra fingers or toes).
Many different diseases may seriously affect the liver, lungs, heart and other major organs to place sufficient stress on a child’s body to delay the production of sex hormones.
In boys, late sexual development may be due to:
- undescended testes (testes remain in abdomen),
- torsion of both testis (testicle twists around and cuts off the blood vessels that supply it),
- Klinefelter syndrome (additional X chromosomes matched with a single Y chromosome)
- Prader-Willi syndrome (obese and small genitals).
In girls the possible causes include:
- anorexia nervosa (psychiatric condition of under eating),
- ovarian torsion (the twisting of both ovaries on the stalk of tissue that supplies it with blood and nerves),
- multiple ovarian cysts,
- Swyer syndrome,
- Turner syndrome (women with only one X chromosome instead of two).