As far as my research has gone, there are laws that protect people age 40 and over. But there are no laws protecting age 40 and under, thus you can sue, and it may or may not pass. SS #'s are fair because the last 4 digits are random with respect to comparing ages. In other words, unless the first 5 numbers of 2 people are the same, the last 4 numbers are random.
The thing is most cases that go to courts seem to be in the neighborhood of "my boss makes me do more shizz cause i'm young." obviously, that doesn't have much of a chance and the burden of proof is difficult. However in my case the policy is clearly stated in the handbook. Kinda seems clearly discriminatory based on age.
The real issue is that I was hired at the opening of the business along with 30 some other people. 6 full time and around 24 part time. I was initially a part time employee and I was the youngest, thus last to bid.
Long story short, when the first full timer quit, I was hired full time over the others. Now, 2 years later, all of the other 5 full-timers also quit, so that I have been Full time longest of all employees. Still, when others moved up, their seniority was originally higher than mine, so they jump ahead of me and i'm still last.
This seems a CLEAR example of discriminating based on age, particularly when the fact that I was promoted first, suggests that I had greater merit.