Improving the unborn

Is anyone else bothered by Blair's new bright idea that the goverment should intervene 'even pre-birth' by identifying families likely to produce children who are likely to go on to cause social nuisance? As yet it seems there is not much detail about the precise nature of this intervention, and I wonder what that might be. What confuses me in particular is why this is put in terms of acting to alter the probable life-course of the as-yet-unborn rather than altering the circumstances and life-chances which any child who might be born will encounter. Can we intervene to help the not-yet-existing? Or perhaps Blair has a theory of pre-natal existence which lies behind the policy? I'm not sure which I'd be more worried by -- a peculiar but perhaps excusable lack of thought about the metaphysics lying behind social policy, or a commitment to the odd metaphysics that would be needed if what was said were to be reasonable.