I feel that the "gateway" phenomenon is probably more to do with the participants than the weed (or alcohol for those underage). What I mean is, it suggests you're willing to test limits and even break the law in some cases. At the very least you're up for new experiences. All of this could lead to harder drug use as well, but doesn't have to. I have not used weed, and I neither encourage it, nor condemn it, however I absolutely agree it should be legal. I also have heard from knowledgeable people that it really helps some people with anxiety related issues and makes others worse. That probably depends on use/non-use of other legal or illegal drugs, the person involved and their surroundings and state of mind, and the chemical make up of the strain itself, and other factors.