I propose that the right to create offspring or duplicates, and the right to live longer than normal yourself, should come from the same ration. It's easy to imagine this as money, but I suppose just as slavery is prohibited, you could prohibit trading of the right to other families/entities.

Maybe I'm missing something, but I see no reason to place such restrictions. A "ration coupon" for reproduction only comes into existence when someone dies or moves off-planet or moves away from this space-station or whatever. The deceased or departed or lucky lottery winner should have the right to pass on the "coupon" to whomever he/she chooses for whatever compensation is mutually agreed. Same goes for the heir.

Hmmm. Maybe you are right. It might not be a good idea to have a futures market on those things.