His Spartan Warrior
When youngs boy turn seven, they find out if they can give birth or not. If they can, they're sent off to learn the motherly duties of the house and then marry as soon as they have mastered those duties.
If they can't, they're sent off to become warriors. As warriors, they will fight for their country and die if need be. Once they reach the age of thirty, they can either retire, marry, and raise a family. Or they have the option of just marrying and having a family.
Or in which a sixteen year old Louis Tomlinson can give birth and is engaged to marry Harry. And a coldhearted, thirty one year old Harry Styles, who has chosen not to retire, is engaged to marry Louis.