Actually to some degree this is already happening to some degree. Well not quite as you said. I'm a very small person. Short, petite bodied and I don't weigh enough to even donate blood. The last time I had to take major medication I got very ill from it. It turns out they gave me a dose for an average adult. I don't have an average adults body. I have something closer to a teenager. Last time I brought up this concern that they will dose me too strong based on a body I don't have....they told me the average dose is fine. I still haven't gone back since. I'm terrified of going going to doctors because I don't want to feel deathly ill because they refuse to take my weight into consideration. It doesn't help that all the nurses are fat, and refuse to even weigh me.