Fortunately, his father never beat him, but his experience with domestic violence as a child has stayed with him his whole life:
Such experiences are destructive. In my adult life I have struggled to overcome the bad lessons of my father's behaviour, this corrosive example of male irresponsibility. But the most oppressive aspect of these experiences was the loneliness. Very recently, during a falling-out with my girlfriend, I felt again as though I were shut out and alone, not heard or understood. I was neither, but it was such a familiar isolation that it was almost a comfort and consolation.
Then on December 1, Reese Witherspoon gave a speech at the House of Commons about domestic violence (unfortunately, this aspect has been largely overshadowed by the media's attention on Prime Minister Gordon Brown's mix-up of Witherspoon with Renée Zellweger). Witherspoon is a spokesperson for Avon and Refuge's campaign against domestic violence.
Here is a video of Reese Witherspoon on Friday Night with Jonathan Ross (on December 4), talking about the campaign (it starts at 4:48).