As we decipher our biology and learn to modify and adjust it, we are learning to modify ourselves - and we will do so. No laws will stop this.
People who drink four or more cups of coffee a day - it doesn't matter whether it is caffeinated or decaffeinated - have a reduction in Type 2 diabetes, or a reduced incidence of Type 2 diabetes, of about fifty percent. The same with Parkinson's, although there it is more related to the caffeine.
Retarding the aging process would be therapy and enhancement because it would mean defeating diseases and because it would extend our life span.