Children are not a drain on society, they are society. You cannot have a society for longer than a single generation without children. They are critically important to continuing any society and penalizing people for deciding to have children is backwards thinking.
The idea that a single family body should be the sole people responsible for the development of a child is also a foolish and somewhat modern misconception. The adage of "it takes a village..." comes to mind. As a society, it is our collective duties to ensure that all members of the society are healthy and cared for. We are communal, social creatures who have long relied on community to be successful and raise our children. This individualist perspective is myopic and counterproductive.
Additionally, the value of a human being simply cannot be reduced to what they contribute to the GDP. Children or adults.