Family Values introduced a couple of startling concepts into Doctor Who stories. First of all, something that doesn’t often come into fiction very often at all, breast feeding! It’s a perfectly natural, normal thing. It’s what they’re FOR, after all, not for page three ogling. But people get strangely embarrassed about it. A lot of readers weren’t ready for the idea of Rose breast-feeding The Doctor’s children.

Sorry guys, but that was the key issue of this story with the people of the Dome, perfectly Human looking, with Human behaviour, but unable to reproduce, to have babies, to feed them naturally, because they were all artificial life forms.

Artificial lifeforms who don’t know they are that have popped up in science fiction occasionally. The classic science fiction film (and book) Bladerunner featured one as a central character, and Stargate SG1 had a lot of trouble with a young girl who didn’t know she was AI, and who’s toys, the Replicators, became a real problem for them.

The emotional issues of an AI who thinks he or she is Human were central to both those stories. The same is true here. The attempt to kidnap Vicki and Peter and make The Doctor and Rose produce more children was not the most serious problem they had ever faced, but it was a deeply emotional one that tested them as parents.

The scene at the beginning in which they talk about Chris and Davie arguing with their mother is related to the idea of family which is the key theme, but it also sets up a later story in which the strained relations between Susan and her sons reach breaking point. It was meant to happen sooner but I wanted to build up the idea of a problem first.

http://en.wikipedia.org/wiki/Breastfeeding