` Also false. The stepping stone theory claims that users in time need 'harder drugs' to satisfy them such as cocaine, heroine, .... which is absolutely untrue and purely based on the idea that most (untrue statement btw) cocaine/heroine users at one point in time used marihuana. The same can be said about alcohol and cigarettes, but no-one claims those substances to be the gateway for hard drugs. Major causality/correlation fuck up in this reasoning. Actually major cohorts of pep users (eg. speed and coke) do emphatically NOT use marihuana. The drinking on the other hand, they love :-) Also, the research on sperm quality was done by Herbert Schuel from BUffalo University. He compared 22 weed smoking guys with 59 non smokers. He found indeed that the sperm in marihuana users is more active. This made him assume that they use up their energy too soon, which is purely hypothetical. Also, the N is too small. 22 is really laughable to draw these kind of conclusions. Also, in a lot of papers people from the anti lobby say these data are corroborated by other research. Then they refer to the the research of Sheena Lewis, Queens University who put THC directly in contact with sperm and saw their 'vigour' decrease. No shit Sherlock :-) On the other hand you have the same amount of research that illustrates the opposite: one of the best documented beneficial effects is what Spike refers to: it has an effect on belancing your blood sugar levels (on a cohort of 4657 people) , making people thin, even after having the munchies too often :-) Check it before you wack it. American journal of medicine. http://www.sciencedirect.com/science/article/pii/S0002934313002003 or if you are a diabetic http://www.sciencedirect.com/science/article/pii/S0002934313003136 To top it off .... Research from The Trimbos institute in Holland where weed is readily available and permitted have illustrated that the legalisation actually resulted in a lower weed consumption all round - AND even in heavy users. EG. heavy users on average/year in Holland : 310 grams - in England 374 grams/year. Report is average users use less, by smaller portions and exhibit significant lower amount of aggression. Example: the Hooligan comparison when Belgium/holland organised the European championship. They want all fighting in Belgium after drinking our beer and none of that happened in Holland. Lol !!! Final not: If you want to save the lungs, vaporize it. No burning proces here.