If it would be treated as a kind of plastic surgery, except on a cellular level, then I'm against it. The reason being, a person usually would commit to appearance altering surgery because they are uncomfortable with how they look, this is a mental problem not a physical problem and by allowing such a person to do this, it doesn't necessarily solve the underlying problem. As a medical tool however, it could save a lot of lives, which is both good and bad.
Was talking about this in Biology today, apparently one of the major concerns is to do with where scientists get the stemcells from in the first place. They 'grow babies' then kill them at 8 weeks and harvest the cells. This is what I've heard.