This post is entirely self serving and misses a key point: Why would I want the world's largest advertising company to have access to my healthcare data?!
The answer is, supposedly, data portability, which is a pain in the ass from hospital to hospital, or even doctor to doctor in the same hospital system. My wife, a nurse, has horror stories about how they sometimes have to fax info to other departments, just to have it re-entered into the same software.
Also, Google doesn't advertise on their Health product.
Just a silly story: some hospitals here in Norway print out patient-information, get an ambulance (an ambulance!) to drive it to the other hospital, and a nurse will type it into the other system (45 minutes she says it takes her). 2011 AD. http://www.nrk.no/nett-tv/indeks/250622/
Also, Google doesn't advertise on their Health product.