Discussions of what I believe and what others(who surround us)believe may take place at any age...

Depends on what the end goal is. To instill the doctrine of religion, begin at conception. To explain our view of religion, when the child asks. No Santa did it for me on the religion topic.

They shouldn't

On the 5th of Never.

That depends on what you mean by religious instruction. If you're talking about a secular education of comparative religions, when they have reached a stage when they are able to understand and process abstractions. Some time between 10 and 14 years, I imagine.

If you are referring to religious indoctrination of any kind, that should never happen. If as a young person is approaching adulthood ( commonly accepted age of 18 ), then the decision rests with them.

Life plus 1

When they are old enough know the difference between science and fairy tales

Children. That's the operative word. Never is the answer.

Leave those kids alone!

90

instruction ? can't a so called god do it, its all a fucking joke

I grew up in San Juan, Puerto RIco. It is a colony of the US and education is not a priority. So my parents put me on private school to get a good education. It was a Catholic school. There was a combination of lay teachers and nuns. The nuns spoke English only so that is why I know English. We were taught religion. At my early age I found out I could do other homework during religion class. Some of my fellow students are more Catholic than the Pope. Not me. I rebelled. My questions were not getting answered. That is when I became atheist. I must have been 8 yrs old when I had my doubts about a man in the clouds watching everything I did. I have a son and a daughter, each from a different marriage. Both are atheist. It was not hard with either of them. They both lead nice lives and I am very proud of them. They both went to public school in the US and are OK with no religious hangups. I live happily without the burden of religion and at 64yrs old, I am not going to change.

Eleven.

Well, if they are raised in an atheist household then I wouldn't expect them to receive any religious instruction at all. But they will almost certainly be exposed to religion through friends, relatives, classmates, entertainment, teachers, coaches, etc. And they will likely have questions about what others are saying. At that point they should receive an explanation about religion, but I would not consider that religious instruction.

My daughter used to ask me about her friends' religion/going to church, etc. This was early on...in elementary school. I always told her this was something SOME PEOPLE did but that WE DIDN'T. In middle school, she was interested in attending church with a friend and I said "FINE. Just think very carefully about the things they're telling you." It was fun for awhile (I suspect there might've been young men involved) but...it never "took."

My point here is this...you take it a little bit at a time. It's like sexual discussions...you listen to what they want to know, answer that question but don't go into more unless they want to hear it.

as early as possible, it's additional knowledge for them, to balance their person and being. If you're a good guardian they'll know what to do at the proper time and I wouldn't think that it's a waste of time

Santa Claus , Easter bunny , death of relatives or pets , disease / sickness among class mates or teachers , and certain spoken words as " god bless u " after a sneeze will get kids attention at any age pretty much . The parent has to make a decision if willing to explain facts or willing to lie . If willing to explain facts , then the parent will need to explain world religions in some extent that appropriate for child s developmental age and mental capacity .
Kids observe constantly and if good relationship w parent then they ask questions . From the Buddha statue at department store to the cross in front of a church, kids ask questions at any age . It comes down to " uncle john is dead for forever " vs " uncle john went to be w the lord ".
Unfurtunately for religious folks , 4th grade and after science classes will explain much mystery and much progress and process ?

21, that way they can drink alcohol instead of the kool aid.

I was a product of a private Catholic school in Puerto Rico. The school was run by priests from Spain and American nuns. The nuns taught. The good thing is that I learned English as the nuns spoke English to the students, even if they knew Spanish as some of them did. I became radicalized against all matters that dealt with religion, any religion. I got worse when I studied electrical theory which is a branch of physics. I had electrical theory and labs where we could prove the equations to real, live electronics. A few years later I landed a job working as a federal contractor in a US and National Guard base. All of that convinced me there is no old man floating in the clouds looking at everything I did. Working for an aerospace corporation doing $1,000,000 fancy radar detectors for the F15 & F16 aircraft.
The physics involved required no god for them to work and they did work. Quantum theory does not require a god that created all. On the contrary. I am a full fledged atheist and my son and daughter both are at the very least agnostics. I never pushed religious dogma to them. All I said to them was not to believe anything that has no way of verification and require evidence to prove what they have heard. So they have no religious hangups. They are OK with learning history even though religious "history" is full of myths and things that are really hard to believe.

Depends I suppose on your goal for teaching them about religion. For me I was raised Protestant by two teachers and never remember believing so much in "God" as finding value in the ethics and morality of religion. While simultaneously questioning and being annoyed by the literal minded and the people who used religion as a tool for hate and judgment. Certainly such things as ethics are not exclusive to religion yet for the expanse of human history myths and religion have been the bedrock of moral teachings. I think a better question might be at what age do you teach children how to behave? And what structure and information to you use to encourage and instill a ethical/moral outlook? What purpose do you instill through such teachings. One of the things I find interesting is how many conversations here on this site center on the uselessness of religion. Ignoring, it seems willfully, the fact of its influence on so much of history or focusing entirely on its negative aspects. I would love to live in a world without it were all people worked together for common goals simply based on reason. But humans as a group and a species do not work that way. One thing I think helps is when instead of concentrating on a person or entities negative behavior as a blanket condemnation of an entire group instead we look to the specifics of an event and look for solutions. If logically the solution is the end of an entire group well there you go. But within large scale religions as within nations, ethnic groups etc. there is no absolute moral or ethical rule in play. The abusive priest is not a condemnation of the priest who does good works. The coach who abuses or father, mother etc. Does not erase or destroy the relevance of the good coach etc. So if we really want to educate our children educate them that their are no easy answers and a person or groups actions are far more relevant then their reasons. For example if someone say a human service worker helps out abused woman and their background in Christian theology gives them the motivation for their work but they apply logic and reason to help their charges. And another similar worker does the same without religion. If they both achieve the same result then why does it matter? If the first example attempted to force their religion on her or his charge then certainly she or he should be censured. But the fact of her belief alone in and of itself is not to me relevant to the job. The question is not why you do something but what you do. The why can certainly influence the what and if the why needs to be addressed to alter or correct the what then it should be. But the blanket attitude that religion is negative period is flawed. To me one of the greatest weaknesses of secular and Atheist thought is the ignoring of the power of belief as a tool for social power. Not just belief in religion per se but belief in an idea and through that idea motivation for action. Its role in purpose were in a cold world of pure reason none exists. I want a Atheist to leave religion behind and tell me this is what we replace it with. This is the reason for humans to not just give a shit about themselves but everyone else

Friends are a very important part of a child's life and many discover religion through association if no one else informs them. When the questions come, teach them to ask their own and approach with an open mind and they will make their own decisions later in life when the time is right. It's an understanding that we have to live in a religious based society and our children must survive within it. Hopefully they will do well.

NEVER

My kids knew the Rabbi and Imam and we hosted Tibetan monks in our house. The monks take butter in their tea.

Whenever the parent think is a good time.