In order for the human race to survive, and evolve, protection of the children and females was necessary. It is a genetic trait for men to do this.

When I was young, I was told by my mother that when walking with a lady, a gentleman takes the street side of the sidewalk. I later learned that this goes back to olden times, when horses and animals were often in the street. Some women who are comfortable with themselves are still charmed by these token acts of chivalry.