Having a low MCAT or GPA balanced by strong EC's can only go so far. Remember that all these numbers we hear (av GPA 3.5 , 29 MCAT)of people who matriculate are all averages, meaning there are people above and below these numbers getting in. For the most part, a school is looking to compensate with your numbers - high GPA to offset low MCAT, or vice versa. EC's are more like icing on the cake so to speak. The main point is that you have to think of your entire application, not just your MCAT or GPA, when asking yourself this question. Also, take into account the kinds of schools you want to get into. Example, a 27 is a decent score (a little on the lower side) for a second tier school, but pretty much no good for a top tier school. If this is your case hypothetically, then you better have a strong GPA, letters of rec, and EC's to hope for an interview at such a school. By the inverse, does this mean having a 34 MCAT will get you in a top school? No, it does not. So having a low MCAT or GPA works against you, but having a strong MCAT and GPA is a requirement but not sufficient to getting into a top school. The higher you go up on the medical school echelons the stiffer the competition and the more "perfect" you have to be in the minds of the adcoms to get in. Good luck.