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 typically conditioned on the successor or recipient reaching a specific age or graduating from college. Most people do not see any debate in these conditions.
What occurs if a condition is controversial? Are there limits to the conditions that you can set?
There are certainly limitations, however they differ somewhat from state to state. Typically, you can not require anyone to do anything unlawful or naturally hazardous. But, what about making an inheritance conditional upon the beneficiary getting married. There does not seem to be excessive controversial about that. What if the individual does not want to get married? What if he or she is homosexual and resides in a state that does not allow gay marriage.
The point is not to suggest that you should not leave conditional inheritances. You should talk to an attorney about the limitations to the conditions you can set and the wisdom of setting conditions to manage someone else’s habits.