Someone just argued with me that gambling can be done by kid too.. 
Absolute nonsense! Gambling is all about real money and high risks - not to mention it can cause strong addiction.
So, I'd say gambling is one of the worst things for kids.
Yeah, kids are not ready to lose their money on gambling but adults are ready and have self control on gambling. If kids do gambling, it's really risky for them.
kids don't have money of their own but only the money that their parents are giving them so losing it would be like losing another person's money and since they only receive a small amount of money they can't really lose a lot but it is still wrong for kids to play gambling.