Marvel's X-Men reboot has just quietly erased millions of mutants from existence. And we're not referring to the X-Men heroes who just died ahead of the relaunch. The history of mutant-human relations is a troubled one, as typified by the creation of the Sentinels, gigantic robots created to hunt and kill mutants. Throughout history, countless others have attempted to slaughter mutants, ranging from religious figures like Reverend Stryker to political leaders such as Graydon Creed.
Mutant history has been punctuated by a serious of acts of genocide and near-extinction-level events. One of the most breathtaking acts of violence against mutants was committed in New X-Men #115, when rogue Sentinels attacked the mutant nation of Genosha. Some years later, the Scarlet Witch altered reality itself to almost erase the X-gene from existence, deactivating all but a few hundred of the world's mutants. It took the power of the Phoenix Force to restore the mutant race.
House of X #4 has just quantified these horrific events. According to this comic, before Genosha there were 17.5 million mutants on the Earth; the attack on Genosha slaughtered 16.5 million of them, leaving just 986,618 remaining. The Scarlet Witch then depowered all but 198 of them. The numbers are staggering, and they turn the Genoshan attack into a near-extinction event in its own right.
There's just one problem; the numbers don't work. For these numbers to be right, all but 1 million of the world's mutants had to be living on Genosha at the time of the Sentinel attack. Suffice to say it's unlikely that a demagogue like Magneto could successfully appeal to such a high proportion of the mutant race. In fact, New X-Men #115 itself states that a little over half of the world's mutants lived on Genosha.
These numbers are reinforced by the post-Genosha X-Men stories; over the next few years, Xavier's Dream of mutant-human coexistence actually seemed possible, with mutant communities growing all over the world. That was why Scarlet Witch's depowering of all but a handful of mutants was such a shock; as Emma Frost reflected in Decimation: House of M - The Day After, before Wanda Maximoff there were tens of millions of mutants, to the extent that Emma dreamed of the soon-coming day when mutants would inherit the Earth. For the sake of accuracy, it's also worth noting that Scarlet Witch left more than 198 mutants with their powers, too; as the comics noted time and again during that period, the 198 were simply the easiest found mutants who headed to Xavier's for sanctuary.
The simple fact is that Hickman's numbers just don't work. Ironically, though, this isn't entirely his fault; the original continuity error was made by Brian Bendis, in House of M #8, the issue where Wanda lashed out at the mutant race with her probability-manipulating powers. This issue was the one that claimed Scarlet Witch only depowered a million mutants, a statement that directly contradicts all the issues leading up to it and running from it.
It appears that Hickman has simply continued the mistake, presumably only having read the main event comics themselves (not shocking, considering the 'redefinition' of the entire X-Men line he's been entrusted with). That may also explain why some of the characterization in the Hickman run feels off so far--keeping the facts of the main stories but starting fresh on the characters' personalities for the purposes of the new story.
House of X #4 is on sale now from Marvel Comics.