From the Torygraph, and not clear how likely it is actually to be put into practice; but it's worrying that it's being considered. Firstly, it's one thing to punish a parent who deliberately keeps their child off school, for instance to help with household chores; and another to threaten parents who are already feeling inadequate in the face of rebellious children. It is hardly going to build up their authority; and more generally, people should not be legally punished for weakness, only for crime.
Moreover, and on a more general and serious point: I think that it's one step in a very ugly direction of making benefits a reward for good behaviour, rather than a response to need. If somebody acts in a way that is seen as deserving a financial penalty, the courts already have, and frequently use, the option of fining them. Using benefits as a carrot-and-stick is getting us back to the old days of the workhouses, etc. Which I'm sure some Tories would love to do.
http://www.telegraph.co.uk/news/politics/8740201/Parents-of-children-who-play-truant-face-losing-benefits.html