delericho said:
In "The Christmas Invasion", the Doctor regrows a hand, commenting that he was able to do so within 15 hours of his regeneration. IIRC, during that episode he also occasionally breathed out wisps of glowing energy - remnants of the regeneration energies.
Just before Jenny awoke, there was a familiar-looking wisp of glowing energy. Plus, the time frame would appear to fit - the episode seems to take place over only the first few hours since her generation. So, perhaps it wasn't a regeneration as such, but rather a form of this same healing that allowed him to regrow a hand?
That's what I had assumed. I had figured that the Doctor was familiar with the process and able to control his hand's generation, whereas Jenny's healing was more instinct. I could see people being confused though, especially since the terraforming gas looked similar to those wisps of Time Lord energy.
I was also generally pleased with this result, as I liked Georgia Moffet's portrayal of Jenny, and it would have been a shame to have her regenerate right away, bringing in a new actress for any subsequent portrayal.
As to Fast Learner's point, I think the obvious in-story reason for the Doctor not growing more offspring immediately is that it would diminish her value as a person. The Doctor seeing her as a valid person and his child was sort of the point of the episode. The Doctor also regularly meets, forms some level of emotional attachment to, and saves people, or feels hurt by their loss before moving on without replacing them, so I don't see Jenny being different in this respect.
Granted, this is not consistent. The 9th and 10th Doctors have both talked about normal, everyday life and people in both a romantic and derisive fashion since the series returned. One only has to look at the first episode featuring Christopher Eccleston to see him consistently forget that Mickey had apparently died, who Mickey was, or why it would matter to Rose. Sometimes the Doctor seems to care too much about the small picture. Other times he ignores it completely for the big picture.
It doesn't really bother me though, and the same goes for his recently emphasized dislike for soldiers and guns. Is it inconsistent and hypocritical given the Doctor's own past views and actions? I would say so, but he has displayed those traits throughout many of his incarnations. I would not say that this "Do as I say, not as I do" approach is a new things. For all his amazing abilities and intellect, this is certainly one of the Doctor's flaws.
As for not repopulating his race with the machine, I cannot see the Doctor wanting to do this. He clearly has the knowledge of genetics to build one of those machines if he needed to, or otherwise accomplish the same basic task, but he has shown no interest previously in fathering a new generation of Time Lords. Jenny was unexpected, and unique.