Would Internal Review Boards (IRBs) — the institutional committees that hold research protocols to ethical standards—all such a study design to proceed?
What ethical standards come into question? Do you think participants would want to be contacted? How do you weigh one potential ill, the harm of contacting someone who wouldn't want to know, with another, the harm of not contacting someone who would want to be told? How do you notify someone that information they might want to have is available, without revealing too much? What if a subject's twin has died since the experiment — should the subject still be contacted? Discuss any ethical concerns you have.