I do research on sensitive issues (specifically non-mainstream and alternative religious and gender/sexuality identities), and have gone through IRB twice. The process depends on your university, and the issue came up in my preliminary Fulbright interview. If your project uses human subjects (most Fulbright research grants do), I was told that it helps the application in you have IRB approval before you apply. But again, so much of this is the opinion and viewpoints of my campus advisor...