You may remember from your teenage years—at one time you were taller than your older brother, some at home would say ‘big sister’, ‘little brother’. But suddenly that equality was broken—you surpassed your older brother. Such a scene is familiar to many families.

All over the world, men are about 5–9 percent taller than women. On average, boys are at least 13 centimeters or 5 inches taller than girls. Why is this so? There are three main reasons behind this:

A woman’s body develops rapidly during adolescence under the influence of the hormone estrogen, but after that, bone growth stops rapidly. As a result, height growth is limited. Since men have more testosterone in their bodies, bones and muscles grow rapidly between the ages of 14–19.

A gene called SHOX is associated with height in human chromosomes. It is active in one of the two X chromosomes of women and dormant in the other. In men, it is more likely to be tall because it is active in both the X and Y chromosomes.

Since men have been hunting and fighting since ancient times, their health and nutrition have been given importance. Tall and strong men have survived longer, resulting in an increase in the number of tall men over time.