Investigating the origin of AIDS: some ethical dimensions.

The theory that AIDS originated from contaminated polio vaccines raises a number of challenging issues with ethical dimensions. The Journal of Medical Ethics dealt with a submission about the theory a decade ago; subsequent developments have raised further issues. Four areas of contention are addressed: whether the theory should be investigated; whether anyone should be blamed; whether defamation actions are appropriate, and whether the scientific community has a responsibility to examine unorthodox theories.