As far as i've researched on pot use effects, it has does not have any major health concerns if done in moderation. Infact, its said to stimulate your body helping reduce stress; (and on that, a friend of mine took the ACT and scored a 29 the first time, which is respectable, but after he started using pot, his score went up to a 34, which is nearly perfect.)
Also, marijuana has no addictive properties to it, unlike that of nicotine or caffine, which are both highly addicting.
http://www.youtube.com/watch?v=EW6TU2vZe_Y&feature=channel The study they did shows that marijuana actually reduced cancer risk. It hasnt been shown to cause cancer.
As far as gateway drug is concerned, i personally believe that the statistics are very biased on this and not really looking at the drug itself, but the users choices. The fact that it is illegal steers many people such as myself away from doing it. Most of the time, the people who smoke pot constantly also do other things like cocaine or what have you; because they are already willing to do somthing despite the fact that it is illegal. (I hope i explained this right so everyone understands what i mean)
Sometimes i wonder why alchol and cigarettes are legal. They kill a heck of a lot more than pot; and infact, there have been absolutly 0 recorded deaths due to pot smoking alone. Where tobacco kills 435k per year and alchol kills over 85k!
http://drugwarfacts.org/cms/?q=node/30 <--- source of those statistics
However, if pot is as bad as some people say, then thats even
MORE of a reason to legalize it, so that it can be safely regulated by the goverment. Theres a lot of people who argue this both ways, weather the other one is right, i think it can be agreed that marijuana is much safer being legal than illegal as long as its regulated
http://www.youtube.com/watch?v=Qd2MsBqzraw&feature=related <-- this video is pretty interesting on this subject
Now putting smoking aside, the plant itself cannabis is one of the most useful plants in the entire world. For the fact that it is a
weed, it grows almost EVERYWHERE. They can make cannabis into clothing and food. And scientists have been able to create a plastic with 6x the intregity of steel from cannabis, AND they're developing a new biofuel that burns completely clean however the refining process isnt quite there yet, however the potential is certinally there.
Making this plant legal would most certianly boost our econmy. Instead of mass money going to the black market, it can be taxed and a lot more money will be put into the goverment as a result. Also, there will be all that left over money from drug enforcement that can be applied elsewhere (which could include additional funding for enforcement of cocaine, meth and other dangerous drug laws)
On that note, enforcement has gotton out of hand when it comes to pot. infact it got some innocent person killed :
http://www.youtube.com/watch?v=1JUMerq-W9c&feature=channel
None.