If we're going to restrict immigration, shouldn't we also stop some people from having children?
I ask because there's a close parallel between immigration and indigenous births. Both increase the labour supply, which could (arguably) force down wages. And both introduce into society someone who might over a lifetime be a net cost to the rest of us.
So, if we're going to restrict one, why not restrict the other?
One reply won't do - that we can better predict which immigrants will be a drain on the tax-payer. New Labour thinks we can also predict the indigenous births that will be costly:
Tony Blair has said it is possible to identify problem children who could grow up to be a potential "menace to society" even before they are born.
Low skill and criminality, he's said, are "often passed down the generations."
And remember - the costs to society of indigenous births can be much larger than that of immigrants, as we don't have to pay to put the latter through school.
Nor is it clear that arguments about liberty justify a distinction. Liberty suggests a case for free immigration - people have a right to live where they want, hire whom they want, and choose the tenants they wish. But it's not obvious that there's an equally strong case for giving people unrestricted freedom to breed, as this is an other-regarding action. John Stuart Mill was clear on this:
The fact itself, of causing the existence of a human being, is one of the most responsible actions in the range of human life. To undertake this responsibility—to bestow a life which may be either a curse or a blessing—unless the being on whom it is to be bestowed will have at least the ordinary chances of a desirable existence, is a crime against that being. And in a country either over-peopled or threatened with being so, to produce children, beyond a very small number, with the effect of reducing the reward of labour by their competition, is a serious offence against all who live by the remuneration of their labour. The laws which, in many countries on the Continent, forbid marriage unless the parties can show that they have the means of supporting a family, do not exceed the legitimate powers of the State.
You might think there's an argument from practicality. It's just wildly impractical to stop the underclass from breeding. Maybe. But it's also expensive to curb immigration. It costs £1.6bn - and rising - to try to do so, and with limited effect.
Now, I'm not calling for the state to limit births. All I'm saying is that advocates of immigration control should - if they wish to be consistent - consider controlling indigenous births, because there are parallels between the two.
In fairness, the Stupid Party has seen this. Its recent document (pdf) on immigration said "we should certainly consider" "a wider population policy" (p30).