There is absolutely nothing unusual about making an inheritance conditional on something else. Conditional presents are as old as estate planning itself. For instance, inheritances are often conditioned on the beneficiary or recipient reaching a specific age or finishing from college. Many people do not see any debate in these conditions.
What happens if a condition is questionable? Are there limits to the conditions that you can set?
There are definitely limits, however they differ somewhat from one state to another. Generally, you can not force anybody to do anything illegal or naturally harmful. What about making an inheritance conditional upon the heir getting wed. There does not appear to be too much controversial about that. Nevertheless, what if the individual does not wish to get wed? What if she or he is homosexual and lives in a state that does not allow gay marriage.
The point is not to suggest that you should not leave conditional inheritances. You ought to talk to an attorney about the limitations to the conditions you can set and the wisdom of setting conditions to control someone else’s behavior.