Even though Doctor Who primarily focuses on time travel and the adventures the Doctor undergoes, it also gave a lot of space to romances. Characters fell in love, got together, and broke up, all of this sometimes in a truly extraordinary fashion. As a result, the show has plenty of iconic couples.
The BBC series Sherlock, on the other hand, offers only a limited number of truly significant romantic relationships. Mostly because its main hero, Sherlock Holmes, focuses on his work, not love. And his best friend John Watson doesn't date that much too. If these two shows combined, some of the characters would nevertheless hit it off.
Would Work: John Watson And Martha Jones
Differences in age aside, Martha and John have a lot in common. Both formed a strong friendship with an eccentric genius. They want to help other people, that's why they studied medicine. They're smart and kind, both put a lot of emphasis on friendship. After leaving the Doctor, Martha joined the UNIT and led a more active lifestyle that would suit John's thirst for adventure well.
Wouldn't Work: Greg Lestrade And Amy Pond
While Amy isn't as adventurous as her daughter River, she still likes to lead an exciting life. Lestrade, on the other hand, experiences a lot of excitement in his line of work - sometimes perhaps too much. He gives off the vibe of a man who just likes to relax after work and not have to deal with the serious stuff. He and Amy might hit it off at first but in the end, they might find out they want something different from life.
Would Work: Molly Hooper And Rory Williams
Molly hasn't had the best of luck when it comes to romance. She was desperately in love with Sherlock but he never saw her that way. Rory did better. He crushed on Amy for years but they finally got together. Molly deserves a guy who would be there for her, and Rory could be that guy. He's painstakingly loyal to those he loves. He's not as adventurous as his wife Amy which would suit Molly's character. Plus, both of them work in similar industries - Rory as a nurse and Molly in a morgue.
Wouldn't Work: Molly Hooper And Jack Harkness
Ironically, Molly would be much more likely to fall for someone like Captain Jack Harkness than the much more suitable Rory. Jack isn't a bad person. He treats people well, has a sense of humor, and is intelligent.
Unfortunately, Jack isn't the best person for long-term relationships. Not only does he lead a dangerous lifestyle but he's also immortal. He wouldn't be able to stay with Molly forever, not without some serious difficulties.
Would Work: Sherlock Holmes And River Song
Sherlock only has one significant almost-relationship on the show. He's not that much focused on things such as love. But River would be the person to change that, at least for a while. She's at first similarly mysterious as Irene Adler, the woman who captured Sherlock's attention. Considering her lifestyle, it's easy to tell River is adventurous, intelligent, likes to play games, and all in all, she and Sherlock would most likely be on the same level.
Wouldn't Work: Mycroft Holmes And Rose Tyler
Even if Rose wasn't so much in love with the Doctor, she and Mycroft have too different personalities. Mycroft doesn't seem like the funniest person to be around. His sense of humor is complex and not everyone gets it. Rose would either get bored with him or roll eyes at his behavior. Mycroft, on the other hand, might think that Rose is childish and/or overly emotional. No, there would be no love lost between those two.
Would Work: Jim Moriarty And Master/Missy
The two craziest people on each show would no doubt hit it off. After all, Missy/Master is to the Doctor what Moriarty is to Sherlock. It's easy to imagine them how they're plotting a deadly plan together, intend to amuse themselves. Both Moriarty and Missy/Master have little respect for human lives.
They're cunning, highly intelligent, and determined to have fun, no matter what it takes. If they joined forces, they would be almost unstoppable.
Wouldn't Work: Sherlock Holmes And The Doctor
Sherlock would no doubt make an excellent companion. Intelligent, inquisitive, and with a drive to help, with a thirst for adventure - in many ways, his character mirrors the Doctor's. However, it's difficult to imagine a romantic relationship between them. Too similar personalities often clash and can't make it work long-term. Sherlock isn't the most emotional person in the world, even though he changed slightly over time. And the Doctor is also careful about getting too close with his companions - or, people in general.
Would Work: Mrs. Hudson And Wilfred Mott
Mrs. Hudson has quite an adventurous past. Nowadays, she lives a much more peaceful life - as much as her life can be peaceful with Sherlock Holmes as her tenant. Donna's grandpa Wilf also likes adventure and travel. Nobody says people can't find love even when they're older. Mrs. Hudson and Wilf are both kind people who have a sense of humor and they would bring joy into each other's lives.
Wouldn't Work: Eurus Holmes And Mickey Smith
When Mickey finally gets married, it's to Martha Jones. She and Eurus possibly couldn't be more different. Both are intelligent but that's where the similarities end. Martha is stable and kind, while Eurus is unhinged and can be cruel. She toys with human lives and can't be trusted. Mickey would avoid Eurus from afar.