I think non-religious households teach morals in much more understandable way than religious households.
Religion says - you do x because god/scripture/prophet/whoever says you must, and if you don't you will be punished after death. Some of the rules may actually be unethical or immoral by other religions - which can cause problems.
AtheismLack of religion says - understand the right thing to do and treat others accordingly. You may not get the same treatment back, but you would hope you would. This behaviour should not cause problems.
At the end of the day, the effect should be the same - we should be nice to each other, be non-judgemental, supportive, loving and kind, no matter what religion someone may or may not have.