5 Reason because Pokémon isn´t for kids:
1º: there are a lot of parameters in eah pokémon(IVS and EVS)
2º: the types´ table is very difficult for a kid.
3º: the breeding is bored and it can last weeks
4º: there are a lot of attacks with various effects
5º:Is difficult the creation of a equilibrated team

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Sorry for my english :p