oops, sorry to re-ask a common question 🙂 but as always I appreciate it.
true, don't have to worry about this for a long time. should probably get in somewhere first.
My PhD is in organic chem, so there will definitely be a different focus for me in residency. I'm finishing my first year of med school now, and it has reminded me yet again why I avoided bio in the first place.
All kidding aside, I think that no matter what you do your PhD in, you can imagine multiple specialties where you could use it. Even in my case, I can come up with at least half a dozen ideas. The most obvious one is anesthesiology (drugs and pharm), but also IM (lots of chem and drug-based subspecialties like ID, nephrology or hepatology), psych (addiction), EM (toxicology), path (clinical chem), or maybe neuro. There are probably lots of other things that I haven't even conceived of since I have yet to begin my rotations. You will probably find the same thing to be true for you too.
Also, FYI the AAMC has a website you can use to help you figure out what specialties might be good matches for you based on your interests, personality, values, and lifestyle preferences. You can't access it until you start school, but once you get there, ask your student dean for the code to give you access.

to you.
🙂