I think if you want to do MD or DO, and your heart is really set on it, PA wouldnt be a good choice as a "backup" plan. There is extensive patient care experience required for most of the masters programs, so you'd have to take that into account too before even considering applying, its not like you'd have an automatic acceptance just because you were a med school applicant, theres lots more involved than just the pre-reqs. Besides, I think people who want to become physicians and people who want to become PA's have different goals to begin with, and are different kinds of people in general. I thought MD was for me when I entered undergrad, but now with a year left to go before graduating, i have no doubt i want to be a PA. My roomate has wanted to be a doctor ever since she could remember, and she's going to Med school next year. It's all about what you want out of life and what you want out of your profession. Simple as that, really. Don't settle for a backup plan, because your backup plan might be someone else's dream that you'd be taking from them. 🙄