My mom was an LP, My wife was an RN (RIP), my last GF was an RN. I've sat in on 100s of medical/oncology and pharma convention meetings to record them. Boring as sin, but ya pick up on a lot.
There are 426 chemical entities in weed. If you have just the wrong genes, and high intake, I'm sure it can cause cancer to that one special person. Burning the vegetation THC Trichomes sits on is not much different than cigs. However cigs have chemicals added to them to keep them burning.
Smoking weed may expose you to the same type of toxic chemicals found in tobacco smoke.
People who only smoked marijuana had higher blood and urine levels of several smoke-related toxins such as naphthalene, acrylamide and acrylonitrile than nonsmokers
There are approximately 600 ingredients in cigarettes. When burned, cigarettes create more than 7,000 chemicals. At least 69 of these chemicals are known to cause cancer, and many are toxic.
That said, Tumor is correct, there is no definitive answer, Yet.
People spend a lot on things that dumb them down, it's a stress relief and endorphin release. if it makes you happy, you'll prolly do it. Everyone sins differently. I'd rather have a weed smoker around me than an alcoholic, I'd rather have a weed smoker around me at work than someone who hasn't slept in 24 hours while working.
That said, weed has some mental issues it can cause. Regular cannabis use can be linked to an increased risk of anxiety and depression. But most research seems to have a focus on the link between psychosis and weed. Using weed can increase the risk of developing psychotic illness, including schizophrenia.
YA know what it boils down to? Life is just too short. Pick your poison wisely. Live your life. Unless someone is willing to volunteer for your place in your coffin, do as you please. What you do is none of my business. I expect the same in return. I'm very busy messing up my own life to keep track of you.