Although the trading is very risky but one thing should be remember that by tolerating failure and taking risk we can go ahead but if we don't face such situations then how we will learn. I think that you should engage your children in such activities because in few years he will just make experience and will do better by experiencing through gain and loss. If there is nothing to do and you have a firm believe that your child will engage in trading in future then surely its a right time to make his concept clear about trading. He will get some knowledge from you and some knowledge will be easy for him because of facing gain and loss situations.
It is a good idea but the age of the children is very essential before exposing the children to all this kind of financial instruments, if they are below 13, I will teach them on paper and the knowledge they need as a foundation and when they come of age like 18+, I will teach them the main trading that will have to do with real money because I will want my kids not to be expose to money at earlier stage of their life. Children are very smart that when they becomes expose to money, they would probably not want to be interested in anything again except money and money.
children under 18 years old would be better taught theoretical knowledge and discipline, this is related to attitude. whereas if it's been more than 18 years, it means their ego has started to form, so we can train them in real trading. with the experience gained, they will match the theory and be able to take lessons from what they experience, so that later they can trade well