That's a head canon thing I expect. But it makes a lot of sense of why Sherlock would be so darn protective of her! That is a terrible theory! But it is a great reason for them to be so protective! I would personally like to Slap Mycroft in the face now!
“On the fields of Trenzalore, at the fall of the Eleventh, when no living creature may speak falsely or fail to give answer, a question will be asked. A question that must never, ever be answered.” Doctor Who?