I thought it was a myth that marijuana killed brain cells and lowered sperm count, but today a friend and I were talking to a health teacher at my school and she said that it does! I was shocked, because I thought schools were more up to date. Does anyone have any links to reputable studies or anything that cane prove her wrong? Or was I wrong? Does MJ really kill brain cells, and if so, how many? Is it like 2 cells or something, or could it really have a long term effect? Thanks.