Children are expensive. The cost alone is reason enough to consider limiting the number of children in your family. Children require a lot of attention. Each additional child a family has takes away time available to spend with the other children. When the children get older and need more help with school work, this attention becomes even less. The more children a family has,the harder it is for the parents to enjoy doing the things they once liked to do. It is easy to lose oneself while tending to everyone else. Having a big family is not all that great.
When it is possible for families to make decisions about their fertility and to control the size of the family group they put themselves in a much more stable position. Financially and emotionally a family will be healthier when they are in control of their own decisions. Smaller families also put less strain onto natural resources.