Question: why do only girls have periods?

Laura Wales answered on 24 Jun 2015:

It’s basically down to our hormones and how they affect our reproductive organs. That and the fact, the female body is designed in such a way to carry a baby. Having a period is the natural cycle the bosy goes through in preparation to have a baby.

The hypothalamus activates a hormone called Gonadotropin-Releasing Hormone (GnRH). GnRH sends a signal to the pituitary gland to release Follicle Stimulating Hormone (FSH) and Luteinising Hormone (LH). FSH and LH travel in the bloodstream to the ovaries in girls and to the testes in boys and “switch on” the development process leading to sexual maturity.

This is where it differs for girls and boys…..In girls, the ovaries release oestrogen and progesterone. In boys, the testes release testosterone. The ovaries release oestrogen and progesterone. Each month, the reproductive system repeats a regular pattern of events that are controlled by hormones (ie. rising and falling levels of oestrogen and progesterone). Rising hormone levels cause the ovary to develop an egg and release it (ovulation).

After ovulation, in preparation for a potential pregnancy, hormones help the lining of the uterus thicken. Each month an egg is released by one of the ovaries and travels down the fallopian tube. If pregnancy doesn’t happen, the egg leaves the body with your menstrual flow. Oestrogen and progesterone levels fall and the lining of the uterus – comes away and leaves the body (the period). The entire cycle repeats and takes around a month, although it can vary from person to person (average cycle is 28 – 35 days).