I would stick with the medical degree, and try to take as many electives in CS as you can. you also might be able to find a CS minor. What it comes down to is that there are not going to be a whole lot of jobs for Pure Computer Science in this country pretty soon (not that there every really should have been or for that matter were), but, In whatever other career you chose the more you can do with a computer the better you will do. That includes programing. computers will be everywhere (not like now... I mean EVERYWHERE) and the better you understand them the better you will do. On the other hand there isn't all that much to do on computers with computers that isn't already being done by people who love it (so much so that now there actually doing it for free) and who are good at math. If you want that degree to get you started stick with biotech. Oh you also might want to spend some time surfing
http://slashdot.org to get a feel for what the CS world is like.