We are at the beginning of epigenetics as a study. Everything we do may potentially affect our genes. Here ya go Lanarck, you discredited old bastard, you were right all along, and Darwin took all the glory.
So to say that smoking marijuana will affect your genes and potentially your offspring is a total trick. All of your chemical exposure will potentially do the same. Your water. Your food. Your laundry products. Your time on gas fumes spewing highways. Your lotion. Your cigar. Your medications. Everything you do might potentially affect you genetically. And mostly there isn’t a damn thing you can do about it.
Personally, the epidemics of neurodegenerative conditions in old and young, the increase in sexual and identity brain dysfunction, all have me scared as to what we are doing wrong. We should live as clean a life as we can, but we don’t always know until it is too late what we have done wrong. I suspect both plastics and pesticides, as we have only recently begun to learn that these things outside us get right into our bloodstreams. Bisphenol A found in the unused uteri of young women?? That’s scary.
Ban everything - it's for the children.