What are your thoughts regarding harvesting cells as far as a necessity in saving lives? I admire your insight, so I ask "do you think it is morally wrong not too?". Pros should certainly trump cons provided there are restrictions.
You have opened a very large can of worms where it's probably useful to consider what you mean by implying a moral imperative to save lives. As a physician, I have taken a vow to act to save lives, but over thirty-plus years of practice it becomes obvious that oath has its limits, some practical, some moral, and sometimes the two overlap in additive or conflicting fashion. To act so as to save life may or may not be in the best interest of the person who owns that life, and it's important that we always consider what you aptly refer to as the pros and cons.
A simple example of harvesting cells to save a life is a blood transfusion. Certainly, if someone who is otherwise well able to function except that they're undergoing massive blood loss, providing them with harvested blood cells is a very moral thing to do. But then I think back to hearing a presentation about the first liver transplant done in Indianapolis on the Friday of the Memorial Day weekend. The anesthesiologist presenting the experience excitedly recounted completely depleting the Indianapolis metropolitan area of both type specific blood (same blood type as the patient) as well as O-negative (so-called universal donor type) blood supplies in the process of successfully completing the surgery. She did not appreciate my question regarding the moral ...
Some cell harvests such as blood for transfusion, present few moral dilemmas, but even these can be problematic. Stem cell harvest and cloning carry much greater moral implications that may be approached by considering classic philosophical schemes such as utilitarianism and the idea of the greater good. Always, with questions of saving lives, one must ask why we are acting for either an individual or a society and perform the double check on our motives versus the best interests of the person(s) impacted by the act.