I’ve seen a lot of people wondering this on the internet myself and it’s a good question. I think it’s important to bare in mind that there are the three main body types; endomorphic, ectomorphic and mesomorphic as I think someone already mentioned. However, I would personally say that it is definitely possible to at least come close to getting six pack abs for anyone.
This blog post goes into a lot more detail about a lot of it including genetics. Definitely worth a read: http://www.iwantasixpack.com/can-anyone-get-a-six-pack/