Sixpence: That covers a broad spectrum. You said yourself there has to be some laws, and you will need armed goons to enforce them.
Absolutely, the laws protecting citizens from agression against their persons and property and the laws enforcing the contracts.
Any citizen is takes upon himself an obligation not to agress against the other citizens and the state enforces it.
Since an abortion-minded citizen could not have possibly taken a voluntary obligation not to agress against his own fetus, and he/she could not have incured a voluntary obligation to let anyone protect that fetus, there is no case for regulating such private behavior.
Not saying it should be moral. Just that it should not be regulated by the state.
miko