Personally, I went back to school for exactly the same reason - to study genetics. Its amazingly interesting and you'd think with the genome project recently, thatd there would be a ton of jobs out there. There are - theres just that many more people out there looking for them so getting one is easier said than done. As Kami has demonstrated, bio and biochem are not the most lucrative of positions, due to the oversupply.
I realized three major things since going back to school.
1) Genetics IS very interesting. It is also complex beyond belief - mendel didnt even begin to scratch the surface, and all that youve heard in HS and the media is a VAST oversimplification. Evolution is the same way - vastly more complicated than the oversimplifactions you get in the media and HS, but once you dive deep enough into it, it will aggravate you to no end when you bump into to people who don't "believe" in it. Its not a matter of belief, its a matter of understanding, which will be self evident to you before long. And while the genome and evolution is interesting, it was also very boring at the same time. Its like studying blueprints. After taking a number of courses, I found my real interest lied in the products of the genome - cell bio, physiology etc. If you think any manmade machine is complicated, the cell and body puts it to shame by orders of magnitude. I am still in awe that any biological system lasts more than a microsecond without imploding under its own complexity, let alone an entire body with trillions of cells lasting for decades. I mention this all because while it might seem interesting to you now, when you get really deep into it, your awe at it may be replaced by disdain for the fact that its nearly impossible to grasp your mind around it, and what used to be fact is ALWAYS changing. Your intro bio books will be full of facts, and your upper level books will be full of "we think..."
2) Getting a job is VERY important. I learned that hard lesson after my first degree (psych). I originally had planned to do the whole nine yards in molecular bio, but then I realized that the prospect of spending 2 more years in undergrad, 4-5 more years in grad (20K a year) and 3-4 more years in postdoc (30K a year) all with huge workloads (60-80 hrs a week), just to have zero job security after all that just wasnt worth it. I ended up going into cytotechnology (diagnosis of cells under microscope - finding cancer in pap smears etc), since I still got to work with cells and the like. My courseload is 120 credits crammed into 2 years. I got one week off for winter, and I can expect to spend the majority of my summer with my face inside a corpse. (gross anatomy FTW) I get to spend my next summer working full time for zero pay, and then get to take a licensing exam. Once I pass, pay is 60-70k with full benefits. Best part is that all it costs me is $3K a semester for tuition at SUNY. The work itself can be pretty monotonous - you have to have an antisocial streak somewhere in your body to tolerate this kind of work, but its well paying from the start, and your job is as secure as it gets.
3) You dont just up and decide to go to med school at some point in your college career. If you plan on getting in, you had better be determined to get an A in just about every course you will take from the start, ESPECIALLY organic chemistry. You are not a special snowflake that will enjoy orgo, it is universally painful to even the best of students; I liken it to teaching calculus to an infant. You had also better do plenty of volunteer work, and independent research. Then be prepared to take out about $100K in loans. Your first two years in med school will be full of very difficult courses, all at the same time. Your final two years will then be more practically oriented, and its not a walk in the park. Then the best part is residency - $40K a year for 80-120hrs a week of work (enjoy 36hr shifts), for 3-5 years depending on your specialty. Don't get settled in anywhere, because youll be hopping around the country in order to get through these few years. Then you can enjoy your 100-200K salary, but also be prepared to work 40-70hr weeks, depending on your specialty. You will also have the lives of others in your direct hands, and if you can't bare that responsibility, don't even bother.