Get real, will you?
I'm advocating freedom from busybodies, not doing harm to the unborn.
1. There is no real danger to unborn children if there mother smoke.
2. People that criticize mothers that smoke should mind their own business.
If your argument includes #1, then I think that should be the debate. Go ahead and try to make the case that smoking does not harm the unborn.
But if you are arguing #2 without establishing #1, then you are saying nothing other that "it's my body, so it's my choice."
And to go just one step further, if a non- (or anti-, whatever) smoker confronts a pregnant woman who is smoking based on a good faith belief that the smoking is harming the child, isn't that person defending the unborn? If you have a response to them, shouldn't it be only to inform them that they have been "duped" by the anti-smoking forces on this issue?