What is an alternate way to become a geneticist, other than by earning a Genetics degree?

Well, the question is self-defeating. Your knowledge and commitment to biochemistry, math, and especially classic biology courses is imperative. And, yes, it would behoove you to go straight toward a Ph.D. in genetics. The competition will be VERY keen, especially from foreign students who are having their education paid for by their home countries. American students do not have that luxury.

Study hard. Start scouting for scholarships. Look for an internship at a genetics lab in your area.

Good luck.

If we are starting at square one, you'll need to get a 4 year degree in something applicable to the biological sciences. It could be chemistry, math, or computer science even - all these skills can be useful in genetics - or it could be just a traditional biological sciences degree like genetics, biology, molecular biology, biochemistry, etc. During this time if you want to end up doing genetics research in something like aging, you'll want to volunteer in a lab as an undergraduate. Even if you are already out of college, I'd suggest looking for a place to volunteer and see if you like research. Many people do this so you should be able to find a professor at a university who'd let you volunteer.

Now after you do this you would want to apply for a PhD program if research is your goal. After 5-6 years of hard work doing research with a professor you'll get your PhD. If you are successful and publish a few good papers then you will apply for a post doc (provided you don't want to do industry biotech research which may or may not require a post doc). This is kind of like graduate school but a little more independent and can last any where from 1 to several years. If you continue to publish successfully then you can apply to professorships. It's pretty competitive to get an academic position. I recall hearing once that something like less than 20% of Stanford PhD students will end up with an academic positions, but I don't remember a source so I'd recommend looking that up for a more solid number, but it is definitely less than half. It is quite competitive for academic positions, but there are other places to do research like biotech companies such as Genentech.

If you are interested in some other type of career in genetics (such as genetic counseling, working as a technician, etc) let me know and I can give you better advice. This is very general advice as to how to become a professor in genetics. Again, the first step I'd say is to reach out to a lab and volunteer to get a taste for research. If you are an undergraduate this is easier, but it is not impossible for people who are not undergraduates. Best of luck to you