Is it sinful...

...for parents to send their children to public school?
...for Dad to stay at home with the children so Mom can work?
...if a married couple decides not to have children?

In a sense everything we do is tainted with sin, for our righteousness is as filthy rags. However, I see issues like those above as wisdom and glory issues, not as scandalous sin. Sending your children to government schools shows a lack of wisdom. A stay-at-home Dad and a working mom reflect God's glory poorly, as do most married couples that decide against children. These are generalizations, there can be exceptions, but they are not the rule.

Some say that churches should restrict the privileges of members who do such things. However, seems to me punitive actions are to be reserved for scandalous sin (such as adultery, divorce, etc). I'd rather the elders model a wise and God-glorifying lifestyle, let their convictions be known in all the church, and leave room for their sheep to follow over time.