My officemate went to a day-long discussion of this sponsored by Dartmouth Medical School. Apparently they had good arguers on both sides. There was an interesting moment when she leaped to the conclusion that one of the opponents, a woman who holds a dozen patents, probably has patents for competing pharmaceuticals and that's why she's opposed - a POV for which she has no evidence but illustrates how we like narratives to explain things to ourselves.
But mostly, what I could see in the written back-and-forth gave me little reason to even reconsider my current view (I was sort of hoping for something more to chew on, you see): Medical marijuana is nowhere near as effective as its proponents claim. Nor is it anywhere near as dangerous as its opponents claim. There are anecdotes of folks who had no relief until they switched to weed, after trying all the approved treatments. But actual benefits that sit still and let themselves be measured by actual trials are harder to come by.
But I'm not opposed to folks having that, even if the value is only subjective, because the harm is not obvious. One can certainly find anecdotes, and one can imagine things going wrong. But the side-effect profile of marijuana isn't that bad, compared to many prescription pharmaceuticals.
This is pretty much my opinion of sex education in the schools and gun control legislation as well. Have it, don't have it, doesn't make much difference in people's behavior. These are symbolic arguments about what sort of people will get to enforce their values on other people. Liberals in cities are nearer both criminals and police. They don't want to be gun-buying people themselves, so they want there to be fewer and fewer guns, as that will increase their safety. They get angry at people who they think are contributing to their danger by not allowing "sensible" gun control laws. People in suburbs and especially rural areas are far from both criminals and police. They prefer a do-it-yourself approach and resent folks who want to increase their danger by taking their guns away. Everyone has stories and imaginations. It's all trade-off, of course, but there seems to be slightly less crime when concealed carry is allowed and there is less gun control.
High school sex education, peer support networks, scarey movies, abstinence coaching, etc - all seem to have little effect, whether for pregnancy or STD's. Yet everyone is just sure that saying X or not saying it is Really Important. Parents seem to have a lot of influence, and choice of friends. Go figure.