Spoiler alert: Do not read until you’ve watched the season premiere of “Doctor Who.”

The moment the Doctor realizes that she is now a “she” goes by in the blink of an eye. Having fallen clear out of the sky and through the roof of a train under alien attack — and losing her trusty TARDIS in the process, no less — the Doctor has more important things to do than consider the fact of her gender. It’s not until someone calls her “madam” and informs her that she’s a woman that she actually slows down to consider the implications. “Am I?” she says, eyebrows raising with mild curiosity. “Does it suit me?”

But she’s quickly back off and running; an alien invasion waits for no one, not even a regenerating Time Lord getting used to her new form (the thirteenth of the series overall). In fact, that question never gets answered directly in “The Woman Who Fell to Earth,” the episode in which Jodie Whittaker debuts as the first female Doctor in over 50 years of “Doctor Who.” In fairness, it doesn’t have to; Whittaker’s deft, frenetic, confident performance speaks for itself. Within minutes she’s made it clear that yes, being a woman suits the Doctor just fine.

When Whittaker’s casting was announced, legions of Whovians made both their excitement and displeasure known. To some, this female Doctor is way overdue; to others, it represented a concession to wokeness by denigrating a classic character. “The Woman Who Fell to Earth” doesn’t spend too much time trying to justify its existence to the latter camp, which is smart. Anyone who made up their mind based solely on her casting is unlikely to change it. But the script from new showrunner Chris Chibnall nonetheless squeezes in a few canny moments to acknowledge the shift, wink at the show’s past, and ably make its case.

As the episode itself stipulates — both implicitly and even a little explicitly — it doesn’t actually matter what form the Doctor takes. The Doctor is an alien time traveler whose life spans thousands of years, regenerating when one form wears out like a snake shedding skin. The real question isn’t “why does the new Doctor have to be a woman?”, as some have gotten stuck on, but “why has the Doctor always regenerated into a white British man?” If nothing else, the previous casting has showed a remarkable lack of creativity for a series that’s long prized itself for its incredible intergalactic imagination.

In fact, last year’s bleak Christmas special — in which Peter Capaldi took his last bow in the role of the Doctor — could be read as an acknowledgement of that very fact. The entire episode hinged on not one, but two versions of the Doctor fighting their need to regenerate: the First (David Bradley, playing the role William Hartnell originated) and the Twelfth (Capaldi). The First said he’d rather die than shift forms; the Twelfth simply felt too tired to continue. But in the end, neither could fight the ongoing march of time, and found peace in passing on to the next thing — which, as it turned out, was Whittaker, a wide-eyed blonde woman with a thick Yorkshire accent and an eye for specificity as keen as any man who played the part before her.

Given the enormity of the occasion of Whittaker’s casting, “The Woman Who Fell to Earth” has to walk a fine line while introducing her. Thirteenth Doctor has to hearken back to the twelve versions before her, echoing their speech patterns and encompassing their storied histories. In acting the part, Whittaker immediately has to both inject her own personality into it and anchor the show. She might not be a brand new Doctor, but a new version of the same character that has fueled the show for decades. Striking the right balance has been a tall order for any new Doctor and showrunner to take on, as several pairs have done over the last decade, but the level of difficulty this particular team had to master is arguably the highest yet.

That’s why it’s so impressive that “The Woman Who Fell to Earth” is, for the most part, an extremely typical episode of “Doctor Who.” The Doctor crash lands on Earth, stumbles into an unfolding alien catastrophe, and accidentally on purpose picks up a brand new pack of friends (played adeptly and distinctly by Tosin Clarke, Mandip Gill, and Bradley Walsh). The Doctor saves the day through a canny combination of ingenuity, bold determination, and a generous amount of luck.

And of course, the Doctor gives a stirring speech about the beauty and pain of embracing one’s humanity — but this is the one area in which the episode more overtly acknowledges that this Doctor is not quite like the others. As the thirteenth Doctor tells her foe in the episode’s climactic standoff: “We’re all capable of incredible change. We can evolve and still stay true to who we are. We can honor who we’ve been, and choose who we want to be next.”

And yes, she’s technically is giving that speech to a serial killer alien with a face full of teeth (long story). But that plea to consider the core of who a person (or Time Lord) is beyond the surface level might as well be the Doctor speaking to the show’s fans themselves. The role can change — the role should change — and still remain true to the spirit of the character and the series itself. Any new actor can honor those who came before, regardless of performance or gender. And as any true fan of “Doctor Who” knows, the ability to choose a new skin or a new way of looking at the world and the endless galaxies beyond it, is exactly what makes the Doctor who he, she, and everything and anything in between, is.