I am not 100% on this at all and there are few studies to support anything in human use. However, from what I gathered in the study and what I found researching, it would seem as though it only effects cell already produced. From that I would think that once usage stopped, newly produced cells would be unaffected. That with the fact that we make sperm when needed and it is not stored tells me that it makes sense. Like I said though, I am not sure on this. Perhaps coop could chime in with some knowledge?