I don't think it is very likely that Tuskegee could happen again. I think that nowadays there are too many eyes on the government to let something like Tuskegee slip by unnoticed. The US government for better or worse is also no longer living in a Cold War mentality where the ends justify the means at all costs. Obviously, it still isn't perfect in respecting individuals, and it has gotten much worse since 9/11 with obvious examples. However, like I said there are too many outspoken people/organizations that are government watchdogs in American society that just were not there in the past.