They could meet during a time-traveling adventure gone wrong, getting stranded in the same era.
It could be in a parallel dimension where their paths unexpectedly converge due to a temporal anomaly.
Well, Jack might meet the 11th Doctor when there's a threat to the space-time continuum that requires their combined efforts to fix. Or it could be a chance encounter at a pivotal moment in history.
It's possible that Jack meets the 10th Doctor when they are both drawn to a mysterious energy source. Another scenario could be when they are brought together by a common enemy with a devious plan.
It's possible that their encounter would be a more serious and emotional one. Jack has seen a great deal of loss and the 13th Doctor also has her own emotional baggage. They could bond over shared experiences, like the loss of friends or the struggle to protect the universe. Jack might offer some unique perspectives based on his long life and the Doctor could in turn show him new ways of looking at things.
Maybe during a battle against a common enemy, forcing them to team up. That's when Jack meets 11.
Perhaps they find themselves in a situation where they have to rescue a group of people trapped in a parallel universe. Jack's skills as a former Time Agent and the Doctor's ability to navigate difficult situations would be crucial in this rescue mission. It could also be a chance for them to learn more about each other's pasts and grow as characters.
It could involve some sort of time anomaly or magical interference causing the pregnancy. Maybe it's a result of a unique encounter with a powerful alien species.
You can start by looking on Archive of Our Own (AO3). It has a large collection of fanfictions, and you can easily search for 'Jack Harkness x Doctor' there. Another place could be Fanfiction.net, although the interface might not be as user - friendly as AO3. There are also some Doctor Who - specific fanfiction forums where you might find some great works about Jack and the Doctor.
Well, 'Journey with Jack and the Doctor' is a fanfiction that stands out. It has an engaging plot that keeps you hooked from start to finish. Then there's 'Jack and the Doctor: Parallel Paths' which is interesting because it shows how their paths cross in unexpected ways. Also, 'The Meeting of Two Legends' is a great read as it focuses on the first encounter between Jack and the Doctor and how it sets the tone for their future relationship.
In many Doctor Who fanfictions, the relationship between Jack and the 11th Doctor can be complex. It could involve mutual respect and adventure, or there might be conflicts and resolutions as they navigate through different scenarios. It really depends on the creativity of the author.
It could lead to all sorts of adventures and unexpected plot twists. Maybe there's confusion at first but then they team up to save the universe!