An absurd and difficult solution to overpopulation that my brother and I created:

Basic Guiding Principle:
(This only applies to the U.S. and Australia, as far as I know)We have some very densely populated cities, but if you took our whole population and spread it out evenly, then we would be quite sparsely populated. So if we maintain our current population fairly then there will be no more problem.

The Rules
1. Everyone dies and so when they die, if they have created no children, the population will return to its original state.
2. Based on the same idea as above, every one person is allowed to have one child because that child will eventually die also, and that child is also allowed to have one child and so on...
3. As a couple, a couple may have two children. This bond as a couple may not be broken. For every child a couple has the parents get one "6" inscribed into their skin and if someone has "666" on their forehead they have broken the law.
4. To redeem themselves they must kill one other person with "666" on their head. This may be done in an organized battle or in the middle of the street. (Most choose to have organized combat for fear of being assassinated in the street. When they do this, they have one(1) "6" removed from their head, and are now legally safe.
5. This process for killing someone must be repeated for every child over the limit, but any murder of someone who is not over the limit is considered a murder.
6. As a single person you may have one child. If you bond with another person you receive their "6" if they have one.
7. Everyone must be properly tagged and identified, anyone who is not must be tagged and identified or killed if they refuse.
8. If you abandon a child you have, that child will be identified with you and your life will be ended for doing so.
9. Every child with no parents will be given to a volunteer. If there are no volunteers they will be given to citizens by force. It is ideal to adopt then to have a child because you will not receive a "6" for adopting a child.
10. It is especially dangerous to be over the child limit because when someone dies when they are at least two (if not more) over the limit, then there is a surplus which is rid by killing someone from a reserve of people over the limit.
11.When a couple has a child, both members of the couple gets one "6", and if one of the members kills someone then they both have one "6" removed. If they kill in battle then they have the choice of which member fights, but if they kill in the street, then it is not of their choice.
12. When someone in a couple dies, two over the limit, then their partner may not be killed because they must care for the children.

If you find any faults in this (besides moral ones) then please /msg me. I also note that I do not believe in this AT ALL. It was just a silly idea.