The world is still trying to come to grips with the fact that everyone's favorite royal couple is expecting a baby, but already attention has shifted to whether that unborn child will one day ascend to the throne of England. (Short answer: Quite likely, yes.) Making things that much more interesting, however: The fact that Kate Middleton has been admitted to the hospital for what St. James Palace says is a severe case of morning sickness (officially called "hyperemesis gravidarum"). According to the National Institute of Health, one possible explanation for the duchess's acute morning sickness (emphasis mine):
Extreme nausea and vomiting during pregnancy can happen if you are pregnant with twins (or more) or if you have a hydatidiform mole.
That's right, twins! Or more! Yes, any such talk of royal multiples is purely speculation. And yes, there are plenty of other possible causes for the duchess's current condition. But the mere possibility of royal twins/triplets/etc. has me and the rest of the newsroom wondering: If there are indeed twins next year, which child will find its name on the top of the succession list?
From my layman's reading of the new royal rule book, it'll be a flat-out race down the royal birth canal. (And, yes, that's a three-word phrase I never thought I'd write, today, or any other.) Things would get really interesting, however, if Kate were to have a C-section, either out of choice or necessity. In that case, the doctor—perhaps with a bit of royal advice?—could potentially be picking the next Queen or King of England. Or more likely, the doctor would follow standard operating procedure but the world would assume that he or she had consciously picked the country's future monarch.
As XX Factor already explained earlier today: Under the old rules that were in place up through last year, a girl born before her brother would have nonetheless found herself behind her male sibling on the royal succession list as a result of male-preference cognatic primogeniture rules. But thanks to the reforms agreed to by the British Commonwealth countries in 2011 (and that still need a go through few final bureaucratic steps before they're officially official), the baby's gender no longer matters. First born is now first born, plain and simple.
I'm far from a lawyer, but it appears pretty straightforward that the new rules would apply the same in the case of twins, giving whichever one were to be officially born first—be it girl or boy—more than just bragging rights over its technically-younger sibling.
Here's how the BBC put in back in 2011 (emphasis still mine):
The leaders of the 16 Commonwealth countries where the Queen is head of state unanimously approved the changes at a summit in Perth, Australia. It means a first-born daughter of the Duke and Duchess of Cambridge would take precedence over younger brothers. ...
"The idea that a younger son should become monarch instead of an elder daughter simply because he is a man ... this way of thinking is at odds with the modern countries that we have become," [said Prime Minister David Cameron.]
So while a multiple royal birth wouldn't appear to actually change the succession equation, it sure would drive home the point of the reformed rules.
Correction: A caption in an earlier version of this post misstated Kate Middleton's formal title. She is the Duchess of Cambridge.