In a perfect market economy the forces of supply and demand would in effect make the relative scarcity of women push up their value.

Imagine a world where bidding wars would ensue for eligible brides, where women, not men would have multiple spouses, and when it came to child birth, parents would insist that given their value, daughters should stay in their maternal household and the groom could join them – for the right inducement, of course.

Many men would face the problem of never marrying and entering old age without children to look after them. As interesting as this scenario would be (it would make a great movie plot), practically it’s not going to happen.

It just so happens that little girls are survivors – around 25% more likely on a level playing field to survive childhood than their male counterparts.

They also have higher rates of survival than males in all other age groups, particularly countries at war or where young men drive motor vehicles – with notable exceptions for countries.