And is that sin? I receive mailings from an organization that is constantly fortifying a bulwark for the family against the pursuing horde. It's enough to make Don Quixote proud. The hubbub this month is all about babies. It seems that Christians just aren't having enough of them. This truly would be problematic if godliness came through reproduction, but that's not Christianity. In fact God gives some pretty glaring examples of god-fearing families gone wrong in the Old Testament, be they large or small.
Jesus didn't say, "Procreate and make disciples." He said, "Go." Not because we shouldn't be passing on the faith to our children but because it is not in our blood; it's in His.
"But to all who did receive him, who believed in his name, he gave the right to become children of God, who were born, not of blood nor of the will of the flesh nor of the will of man, but of God." John 1:13