It's a good sign (though too late for many) that today Tuskegee seems unthinkable. It turns out that the same organizations were doing the same thing in Guatemala too.
I've always found it frustrating that in criticisms of corporate pharmaceutical research, Tuskegee invariably comes up. It's useful to clarify that Tuskegee (and this Guatemalan project) were carried out by government organizations. Corporate America can be proud because it has never undertaken anything remotely as immoral as that. (And as historians dig, there's apparently more still to come.) So if you're worried about how people are treated in medical studies, history would strongly suggest that you should look at those carried out by government organizations rather than private companies.
No one wants more Tuskegees. The best way to ensure that is to know your history.