The Doctor's Daughter does not have much in terms of plot. We're certainly mildly interested in the fate of the Hath and the struggle of the two armies. We want to make sure that the Doctor and his crew of two do what they can to end the war and get out of there before things get serious. The driving force of this episode, however, is characterization. This is a kind of pre-cursor to The Doctor's Wife, in which the plot of defeating House and rescuing the Williamses takes a back seat to the relationship with Sexy. We know for a fact that the Doctor has been a father and a grandfather. The first companion who we met was his granddaughter, so there's no denying his family ties. The Doctor will have no part of it, though. Granted, the circumstances of his fatherhood are a bit sketchy; he is essentially a sperm donor being asked to babysit the result of his donation. His severed hand is more excited about the whole thing than he is. No one seems to like poor Generated Anomaly at first. It seems to be a product of the fact that she speaks only one language: Strategy. The Doctor also protests Donna's calling him Dad by saying that You can't extrapolate a relationship from a biological accident. He spends a great deal of the episode avoiding any kind of connection with his unwanted daughter and this episode's version of the Doctor is one of my least favorite. I admit that he has the universe's biggest case of daddy issues, though in a way that is entirely alien to us. By the end of the episode, he is able to forge a small if significant connection to Jenny. We start to hope that she's going to join the crew and that the Doctor's original fear of commitment is just an unfortunate first impression. The Doctor promises that You've my daughter and we've only just got started. She dies in his arms, only to revive by TimeLordy biological miracle later. She doesn't even have to regenerate. She sets out to see the larger universe and the fans naturally started yearning for another appearance. Three seasons later, though, we have never seen Jenny again. With such a beginning and such a premise, it seems an awful waste. Where did she go upon leaving? Did she ever meet a future version of the Doctor? Are there worlds out there saved by a Jenny with no last name and no parents?