Are you interested in BA/MD or BA/DO programs? These programs offer highly qualified high school students admission to medical school at the same time they are admitted to college. Combined degree programs allow a med school hopeful to bypass some of medical school admission process later on–like taking the MCAT or applying to multiple med schools–provided they fulfill the conditions of the program. (Typically maintaining a certain GPA and sGPA, meeting program goals for clinical and non-clinical volunteering, having a successful med school admission interview, displaying appropriate maturity, etc)
There is a separate forum to discuss these programs:
http://talk.collegeconfidential.com/multiple-degree-programs/
As you might guess, admission to these program is extremely competitive with acceptance rates in the single digits.
To be competitive for these programs, one needs to take the highest level of science & math classes offered by their high school–AP/IB/dual enrollment–to show readiness to do college level academics. BA/MD applicants are also expected to have physician shadowing, volunteering at clinical sites (hospital, medical office, public clinic) and community service with the less fortunate.