Quite some time ago I got into a... minor argument regarding whether or not a ninja could in fact learn a jutsu to which their natural alignment was not geared toward. I felt you could, but it would be more difficult than it would be for someone whose natural alignment lies with that element. The person I was discussing it with did not. They felt it was impossible for a ninja to learn a jutsu outside of their natural alignment.
I stopped reading Naruto quite some time ago but I was wondering if anything came up that answered that question in one way or another?