I believe the responsible thing to do is consider one's financial situation not only today but their future prospects as well. It is just as important to make sure that you and the other parent are committed to doing everthing in your power to provide a loving home which will nuture the child's self-esteem, provide an education, and prepare them to become a self-reliant responsible contributing adult. One of the best gifts you can give a child is making sure that their other parent is someone who wants the best for them.
On a personal note I have never felt the internal need or desire to have children. Therefore I chose not to have them. It goes without saying anyone who doesn't want children should not have them. I elected to have a vasectomy many years ago.