IOne of main purposes of religion it's to stop social ills of society. But it has failed to do so. Usually people never ask why. They question everything but not religion. Why? It is because as children elders, though they try to answer children's questions about the world, stop short when the question is related to religion. They take the easy way out. Give the short answer, religion teaches us it is good or religion teaches us it is bad. May be they don't know how to answer it. It may be better to tell children the truth (Religion force us to do that - but we fail to do so). Better answer may be "I don't know, think about it yourself. Teaching children, not to kill, not to steal and not to cheat, is absolutely necessary. It is easy to identify killing and stealing, but cheating is bit hard, because parents also cheat - sometimes to their own children.
Then comes other ills, sex and intoxication. Here, there is total chaos. Intoxication, parents give examples of mental breakdown of extreme intoxication of drug addicts. Children also could see, sometimes for themselves, but mostly in news about this. They get scared - most of them, but being children some the want to experiment. The wrong message do more harm than good. All drugs don't make addicts, by a single use, - or few. But some extreme drugs do. All drugs heighten pleasure in the brain - well that is why we take them. Different different drugs vary in the types of pleasure and tend to become an addict. The parents don't teach this to children, they say all drugs are bad. But pears will give a different message to children. Sometimes it is more near to truth. For instance getting drunk once won't make you an addict. But using heroin once can make you an addict. Children get confused, parents tell one thing, pears tell another and their experience shows a tendency towards more truth in what pears say. Then they will try to experiment with extreme drugs, and become addicts.
There are other factors that cannot be controlled by parents, but we are messing up with what we can.
Then sex, parents are also confused by what religion says, and all the messages they get from society. So, how can they clear the minds of children? It is definitely better, to be silent on this matter if you don't know about it.
When we are children we learn about death. We get scared and trey to forget it. We question parents and try to convince us that it will not happen to us. The first concept we have in our minds is that we are exempt from it. When we get matured we see more and more death happens everywhere. But still we are convinced that we can find a way out of it. Though religion teaches us that there is a life beyond this life, there is some sort of after life we are not convinced by it. There is an age we start to doubt this concept, that we can beat death. This is the correct age of investigation about religion(may be 40). But still it is not the correct age to learn and be fixed in one single religion. Then comes a age we feel that we are definitely going to die someday, that is the age(may be 50) we should we should fix on one religion.
Messing we this age limits makes mental torment to an individual. Wrist case is suicide, and other things like depression at young age happens. Children should learn to enjoy life. When you are young or brains are geared to it. That is why young people take drugs, do competitive sports, get addicted to video games, addicted to smart phones, social apps, etc. Adults should not try to stop them, but guide them so that it is not harmful, maybe have limits. Emphasising on education to get a good job in later life conflict with this. This is the reason parents and children drift apart in their relationships. The problem becomes worse because all children are not smart in learning and correct method of teaching to that particular child is not applied. Sometimes we try to teach wrong subjects(trying to realise parents dreams through children).