The vulnerability of the individual benefit argument

In "Shared Vulnerabilities in Research" the author argues that research conferring no direct benefit and conducted with a vulnerable group of subjects cannot be morally justified on the grounds that the beneficiaries of that research share the subjects' vulnerability. While we agree that the paper's central argument is valid, we challenge the assumption that one (A) suffers for the benefit of another (B). The author erroneously extracts A from his group (of vulnerable subjects). Consequently, any opportunities or benefits that may come to the group will exclude A. Ultimately, we conclude that it does make a moral difference whether the beneficiaries share the research subjects' vulnerability.