Spoiler Alert

Doctor Who’s final 60th Anniversary special set the show on a new course in more ways than one. Fans went into it knowing that Ncuti Gatwa would make his debut as the Fifteenth Doctor. However, everyone assumed that it would happen the way that all the other regenerations have gone since the show’s 2005 revival. The Doctor gets a fatal injury, starts glowing with regeneration energy, and then we get someone else’s face and body in their (usually tattered) clothing. Well, the regeneration from the Fourteenth Doctor to the Fifteenth Doctor changed the rules of Doctor Who regeneration with a new concept called bi-generation. What does that mean? And what happened to the Fourteenth Doctor in Doctor Who? It’s time to break it down. 


The Fourteenth Doctor and His Groundbreaking Bi-generation

Boom, we are at UNIT with Fourteen, former companion Mel Bush, Donna, Kate, Shirley, and a few soldiers. The Toymaker (wow, did Neil Patrick Harris crush this role!) takes the Galvanic Beam and lasers the Doctor right through the chest. He wants to play another game and beat yet another Doctor. Mel and Donna, who both understand the concept of regeneration, are there to hold Fourteen’s hand as he begins his transition. But things get weird when he asks them to pull his arms in opposite directions. Fourteen (and the entire viewing audience) is very confused as they pull and reveal Gatwa’s Fifteenth Doctor. Both of the Doctors seem delighted to see each other.


Now, this certainly isn’t the first time that we have seen two or more Doctors together, but that’s usually because of spaghetti timeline foolery. Kate questions what happened to the Doctor. Fifteen says it is “bi-generation,” which is supposed to be a myth… until now. The Doctor literally soothes and comforts his own pain, knowing that the Tennant-version of him is in need of rest. And that’s why the Doctor took the Tenth Doctor’s face once again. He needed to find Donna and come home with her. 

This strange occurrence, combined with the “prize” from winning against the Toymaker, also causes another version of the TARDIS to form. Fourteen takes one with him but chooses to stay on Earth and live the adventure of a normal life with Donna, her family, and Mel Bush. It’s quite lovely for the lonely god who kept running for thousands of years to have a family, including his niece, Rose Noble. So, yet, another Tenth Doctor companion gets a version of him to live with. (I guess they figured Martha is okay in the world and fighting aliens with her husband, Mickey.) Fifteen takes his TARDIS and heads towards the stars for more time and space adventures. 

What Is Bi-generation in Doctor Who and How Does It Work?

According to showrunner Russell T Davies, here’s what this new regeneration concept means on Doctor Who. “Bi-generation, we discover, is an ancient myth of the Time Lords where instead of a new body taking over from the old body, the new body separates from the old body, and both are left alive,” Davies reveals on Doctor Who Unleashed. He goes even further to say that the concept of bi-generation has created the “Doctorverse,” where every Doctor is now in separate existence somewhere in the universe. That part is not expressly stated in the episode, so we will see if Davies actually builds the Doctorverse concept into the show’s future.

This is certainly controversial, but it also could be an easy way to explain aging when previous Doctors return. So they are still essentially the same person as we have always known them to be, but the Doctor can now splinter himself. We assume that bi-generation will show up in Doctor Who‘s future when it’s time to say goodbye to Ncuti Gatwa. 

It is possible that the Fourteenth Doctor (and others) are not able to regenerate any longer. We can only assume they have two hearts, unlike the metacrisis Doctor, who only has one. So they will presumably grow old in real-time and eventually die. There are many questions that bi-generation opens up, indeed. But rest assured, Ncuti Gatwa’s Doctor is just as real as every Doctor before him, and we cannot wait to see how the Doctor makes good on this fresh start. With the pain of the past in the rearview, almost anything is possible for the future.