Although choosing to have 2 children will help slow growth, having only one child is better. Best is having no children. If you really want to parent, consider adoption. Here in the United States there are many special-needs kids who need a good home. In addition, there are millions of children all over the world who need caring parents.
Populations grow more slowly if people wait to have their children.
Therefore it is good to postpone childbearing, if you plan to build a family in the traditional way. Finish your education and get your career underway. Most important, be sure that your really love your partner and that your relationship is stable. The United States has been considered the world's most overpopulated country. This is because of our rate of consumption, which is much more than people in most other countries.