This is a tough question to answer irrespective of the fact that we know the total world population to be approximately 7.753 Billion. Again there are countries with large populations example China, and there are countries with smaller populations, thus if we are to provide suggestions or make laws for reducing the world population, the law will not apply to all countries because you cannot enforce birth control on a small country like Tuvalu or a religious city like the Vatican.
If there should be laws aimed at reducing population, they should be targeted at countries with large populations and poor economies. This is to help reduce the rate of demand for food, water, housing, energy, healthcare, transportation, etc. Even with a good economy, overpopulation is never desirable as the effect on the environment is usually not healthy.
The question then is thus, how can the population be controlled, such that the right to life is not taken from unborn babies and the moral beliefs of Christians are not jeopardized?
If you encourage Family planning for couples who have given birth to a certain number of children, there could be difficulty in adhering to such laws for people especially Traditional Catholics who do not support any form of contraceptives, and surely you can't tell an adult who is still in his late 40s not to have sex simply because he has given birth to a certain number of children.
Abortion for couples who have given birth to a certain number of children is not even an option for me. IT IS DENIAL OF THE RIGHT TO LIFE.
What then can be done?
Countries that have seen a huge growth in the population should work towards sensitizing citizens on the need to control the size of their families. Medically, there are safe periods in a woman's cycle when she can have sex with little chance of conception. Couples who are still young but have a family size of four excluding them should consider doing so, even if they have the finance to sponsor ten children. This is because the responsibility for their presence is not just on the couple alone but also on the society and the country at large. Their energy consumption, job opportunity, and transportation all affect the greater mass to an extent.
I believe if people are made to understand the challenges faced in overpopulated countries, they will willingly be of help. Couples who are not financially buoyant do not need special preaching. They are to give birth according to their financial power.
Again, countries like Tuvalu, and Palau with low populations should open their doors to people who may want to live there. This way, the population in certain overpopulated countries will be reduced. Some of these less populated countries are indeed underdeveloped, but the world can help in developing them and making it attractive for noncitizens to move in.
Finally, I believe education and self-discipline on part of couples is the right approach toward reducing the world population. There is no way to have a less competitive world if we do not control the number of people we will bring into the world.
If couples are educated, the irrational motives behind couples giving birth to up to 7 girls to have a male issue in between will stop. Children are children whether male or female. We need to love them equally. I know of a family that has 9 girls. All of them were born with the hope of getting a boy. Today, the family is challenged with feeding the children. If governments should stand up to their duties and individuals discipline themselves, there is nothing to fear when it comes to population.
Just as I said earlier, any law against Life instituted as a way of reducing population is not RIGHT!!!.