Sunday was an exciting day for nerds everywhere, with both the season premiere of Game of Thrones and the announcement of a new Doctor in the British sci-fi show Doctor Who.

The new Doctor made some waves because, starting this Christmas, the heroic, time-travelling Doctor will be played, for the first time, by a woman.

Doctor Who is about a shape-shifting alien—“the Doctor”—who travels the universe in a time machine shaped like a British police box from the 1960s. Whenever the Doctor is mortally wounded, he regenerates into a different actor, a convenient conceit which has allowed the show to run, on and off, for 54 years, featuring 13 Doctors.

But Jodie Whittaker is the first female incarnation of the titular character, which stretches that conceit to the breaking point.

It’s not that the idea of a female time traveler is anathema, but the Doctor is an established male character who remembers and interacts with a half-century’s worth of stories. Sometimes the Doctor was a wild-haired, toothy adventurer with an 18-foot scarf and sometimes a spiky-haired emo millennial in converse trainers, but he was always the same person. The Doctor has been married (four times!) and is a father. In Britain, he’s a cultural icon as recognizable and beloved as Santa Claus.

It’s neither surprising nor ridiculous that some fans (albeit very few) are having issues with the idea that the Doctor just had a sex change.

Much to the disappointment of the internet, the casting hasn’t created much outrage. Yet it seems like an act of desperation. The show’s ratings have fallen over the last few years, in part due to having an older, less approachable lead, and several seasons of tangled, incomprehensible storytelling. My theory is that the BBC was so panicked by poor ratings that it resorted to a PC gimmick to win over the SJW crowd.

And on that count, at least, it’s worked. Adulation has poured in, with former Who actors saying “the BBC really did do the right thing” and it’s “about time. A new dawn.”

Casting a female Doctor will also insulate the show from any artistic criticism, because it elevates the enterprise from entertainment to cause. But who do the showrunners cast next? Where do you go after this great civil rights victory? One of the great lessons of the internet age is that you can never make everyone happy.

Letting identity politics (or more specifically, the whims of a vocal group of online fans) dominate storytelling is never a good decision, and it’s done Doctor Who no favors in the past. Last season, the Doctor’s companion Bill Potts was a black lesbian who was bundled off in the last episode with her magic girlfriend who’d been possessed by an evil water creature. It was a weird ending for the character (even by Doctor Who standards), and felt like a distraction from the fact that Bill never got any character development. It made no sense.

But Tumblr loved it.

I love Doctor Who, and I hope I’m wrong. I like Jodie Whittaker. I thought she gave an incredible performance in Broadchurch, investing Beth Latimer with a marvelous, fierce vulnerability. But I worry that casting her will change Doctor Who so much that the show becomes unrecognizable and perhaps even unsustainable. It would be a shame to sacrifice such a great series to stunt casting. Doctor Who is all about change, yes. But it’s also about a formula: a formula robust enough that it powered the longest-running sci-fi show in television history.