I disagree. Until a person has an MCAT score, he has needs to assume that his GPA needs to be as high as possible. A high GPA can compensate for a less-than-top GPA. If you end up with both a high GPA and a high MCAT, then you're golden, but if you end up with an unbalanced MCAT or a less-than-desired MCAT, a near-perfect/perfect GPA can be a nudge for you.
Since a person usually doesn't know what his MCAT score will be until well into the college process, one should error on the side of caution.
I understand what you're saying, but you're operating under the assumption that the sole function (and benefit) of taking college courses is to produce a GPA that is great for medical school. That's a very narrow view of college and would result in a lot of students missing out on classes that could significantly change goals or priorities.
For example, a particularly memorable sociology class that I took, out of the blue, caused me to drop a double major in chemistry and pursue sociology because I loved it. Another class, an EMT class, convinced me that I didn't want to do emergency medicine and actually pushed me to explore other areas of medicine such as oncology or studying chronic diseases (diabetes, etc). Another class I took out of the blue, a biophysics seminar, made me fall in love with physics and resulted in forming a 3+ year relationship with a professor who has become my mentor and greatest advocate. Along the way, I picked up other classes that were simply great for learning: a philosophy course, which was the second lowest grade I've ever received, but changed the way I look at the world; an economics course which I did worse than I went in expecting (A-) but still would take again because it changed my understanding of current events and understanding society as a community of consumers/actors.
That's what college is about. Learn things you'll never be able to, explore paths that you wouldn't otherwise have the time to. Especially if these are classes that you are already interested in?? Take them! You'll do the best in those classes which you find exciting and interesting.
Let's say you're a student who has 102 credits and a 3.8, and you take six 3-credit classes and average a B+ in them. It would drop your total expected graduating GPA to a 3.73. The difference between those is less than one
LizzyM point, but the difference those six classes could make to your employability, personal enrichment, happiness, etc could be so much more, and that's
assuming you only get a B+ average, which doesn't at all have to be the case.
You don't need a perfect GPA to get into medical school. Even the best schools have
average GPAs in the 3.8 range. It's rare that you can't afford to take some riskier classes, and the potential rewards are great. Don't let admissions define your life, most of the time it's not even that big of a deal.