Question: Is it legal to ask if a student is a first generation college student on a scholarship application?
It's never occurred to “The Dean" to question the legality of such a query, and I'm not an attorney so I can't imagine what law it might violate. Admission officials and scholarship-organization administrators typically gather a lot information about their candidates, and they endeavor to see these candidates in the context of their backgrounds. So asking if either parent attended college is one way to learn more about an applicant although, of course, the answers don't always tell the whole story.
Some scholarships, as you probably know, are earmarked specifically for first-generation students so certainly those applications must inquire about the parents' education. Thus it doesn't seem illegal–or unreasonable—to ask if a student is first-generation. But, as I said above, I'm not a lawyer ... and, when it comes right down to it, I'm not even a dean either. ;-)
I'll post this on the College Confidential forum to see if any legal eagles weigh in.