Sex Hormones

Sex Hormones and Their Roles

  • Sex hormones are crucial in controlling the growth and development of reproductive tissues, secondary sexual characteristics, and reproductive behaviour.
  • They are mainly produced by the gonads (ovaries in females and testes in males), though small amounts are produced by the adrenal glands.


  • Oestrogen is a female sex hormone produced primarily by the ovaries.
  • It initiates the growth of the female secondary sexual characteristics such as the menstrual cycle and mammary glands.
  • Oestrogen controls the growth of the uterine lining during the first part of the menstrual cycle, in preparation for pregnancy.


  • Progesterone is another female sex hormone released by the ovaries.
  • Its primary function is to maintain the lining of the uterus to sustain a potential pregnancy.
  • Progesterone levels increase after ovulation has occurred and decrease if no implantation takes place, initiating the shedding of the uterine lining known as menstruation.


  • Testosterone is the main male sex hormone and is produced in the testes.
  • It promotes the development of male secondary sexual characteristics, such as facial hair, deepening of the voice, and an increase in muscle mass.
  • Testosterone also plays a significant role in sperm production.

Hormonal Balance and Infertility

  • The intricate balance of these hormones is critical for normal sexual development and reproductive function.
  • Any imbalance in these hormones can result in fertility issues. For instance, low testosterone levels in males can lead to a low sperm count, while an imbalance in oestrogen and progesterone in females can disrupt the menstrual cycle and prevent normal ovulation.

Treatments for Hormonal Imbalances

  • Treatments for hormonal imbalances can involve hormone replacement therapy or medication that can regulate hormone production.
  • Healthcare providers can also recommend lifestyle modifications like diet and exercise that may help to restore hormonal balance.