Ultimogeniture

It sounds like a sci-fi story where women are impregnated with genetically engineered alien warriors.

Yeah...no. Although, this one does involve a little pregnancy, at least on the margins.

Any fan of the British Royal Family is familiar with the concept of primogeniture. It means that all the assets of an estate, like the throne of Great Britain, get inherited by the first-born child (sometimes, of course, it's stipulated as first-born son, but the gender part of that is obviously silly and old-fashioned).

Ultimogeniture represents the opposite of primogeniture. Well, actually, it's pretty much the same thing, except that it goes to a different kid. Instead of the first-born, all the inheritance goes to the last-born. So...you have five kids, listed in birth order: John, Tarmore, Parker, Dingo, and Sarah. John is the oldest, so under primogeniture, he would inherit everything when you die. Under ultimogeniture, it would all go to Sarah, the youngest. Let the in-fighting begin.