Smoking marijuana is not for everybody and yes it can have its negative side effects. However, there are some very good benefits to it as well. Granted it is not a miracle drug that will cure cancer overnight, it does help combat some effects of cancer. The anti-cancer properties of marijuana occur naturally through nature, and can be ingested in other ways than smoking to avoid the potential of lung or throat cancer. There is no need to genetically modify anti-cancer properties into marijuana when it produces these properties by itself. Marijuana grew on this earth for a reason, and should be utilized for the benefit of those living on this planet.
One final note is that a major reason marijuana is illegal is because many saw it as a threat to commerce due to its versatility and many uses that would have put a lot of powerful people out of business. Those threatened were in the cotton and timber industries and lobbied for its ban to protect their own self-interest and corporate profits. The first American laws on marijuana required you to grow it and you could be punished if you didn’t.