In a bizarre turn of events, it has emerged that David Tennant, who played the 10th Doctor Who is to get married to the daughter of Peter Davidson, who played the 5th Doctor Who. In effect, he is marrying his own daughter. One would ask the question: "is it legal?"
Although legend has it that Oedipus married his own mother, it has never been a serious issue before. Indeed, there have been no cases ever of a person marrying their own mother-in-law. Although, recently, there have been several cases of fathers siring children by their own daughters, they never actually married them.
Some of the world's leading legalists are currently writing new laws to prevent such an event from happening. One can only imagine that the Timelord has been playing with his sonic screwdriver and it could be a case of 'chronological incest'. If no such rules exist, the consequences for mankind could be horrific!