There are three specific sex hormones you may have heard of--estrogen, testosterone and progesterone. What you may not realize is that both men and women produce all three of these hormones (in different amounts). We call these sex hormones because they are produced in the sex organs--for women in the ovaries, and for men in the testes--in response to stimulation by the pituitary gland, a pea-sized gland in the brain. The pituitary gland stimulates the ovaries to produce estrogen, progesterone and testosterone at specific times and in specific amounts, through the timed release of two other hormones known as FSH (follicle-stimulating hormone) and LH (luteinizing hormone).

Hormones Through the Ages
While we produce these hormones from the time we are born, their production increases during puberty. For females, the increased production of estrogen and progesterone triggers ovulation and the onset of menstruation. In males, testosterone is linked to the production of sperm. Production of these hormones decreases as we age. For women, this change is marked by menopause.  Even though the quantities fluctuate, most of us naturally produce these hormones throughout most of our lives.

The Power of Hormones
In women not taking hormone-based contraceptives, the flow of hormones in the body changes throughout the month, triggering certain reproductive events. For example, after an ovary releases an egg, the empty egg follicle becomes the corpus luteum, which releases large quantities of progesterone, as well as estrogen during the second phase of the menstrual cycle or the luteal phase. When the corpus luteum degenerates, hormonal secretion declines sharply, triggering the start of menstruation. 

When a woman becomes pregnant, hormone secretion from the corpus luteum continues, preventing her ovaries from releasing additional eggs until after her baby is born.  In other words, women do not ovulate or get their periods while pregnant. This phenomenon often continues if a woman nurses, meaning that many women do not ovulate or experience a period for many months after giving birth. 

Each sex hormone has many different functions. In women, estrogen is linked to development of female sex characteristics. For women in their reproductive years, estrogen can trigger changes in the cervix and the release of clear cervical fluid, indicating a woman is fertile. Progesterone is associated with the ability of a woman's body to maintain a pregnancy. 

 
Estrogen is linked to the development of female sex characteristics.
 


Still More to Discover
Like much about the human body, there is much we still don't know about the function and effects of the sex hormones. For example, while it has been hypothesized that the small amounts of testosterone women naturally produce are linked to sex drive, the reason for estrogen production in men was unknown until only recently when researchers found estrogen in men enables sperm to reach maturity, directly affecting their sperm count.

Birth control methods like the Pill use synthetic versions of the body's natural sex hormones in order to prevent pregnancy.  Click here to learn more.

 
 
Progesterone helps a woman maintain a pregnancy.