Good for you. I plan on adoption as well.
So, to control human populations we are going to prohibited breeding, instead of killing those already in existance. How many children can people have? One, Two, none? How are we going to enforce this? Once you have a child, you have to be sterilized? What if, to maintain populations some people cannot have children? How do we figure out who can and can't have children? How are we going to punish those who do have too many children?
People are already preaching safe sex and control to the teenagers. It's not working, teenage mothers are on the rise. It's something that has to either be dealt with or just accepted. My mother-in-law works in an OBGYN clinic and my mother works in Labour and Delivery, both are amazed at the amounts of young mothers.
In 3rd world countries, children are a livelihood. In 3rd world countries you must have many children in order to survive, you have children to help run the farm, hunt and fish. We are pampered in wealthy countries and it is easy to ponder idealistic ways, but the whole world doesn't have such luxuries. In many countries many kids are a way of life and survival, and they have survived for centuries as such.
I understand your point of view, and I am not discouraging you, simply challenging your point of view through a civil discussion.