... In many jurisdictions, people who know they are H.I.V.-positive are legally required to disclose this status to potential sexual partners, even when they intend to engage in relatively safe and protected sex. Why do our disclosure policies single out this group, and not, for example, people with other incurable, or possibly fatal, infectious diseases? Why do most policies demand transparency between sexual partners in regard to their H.I.V.-status, but not in regard to past behaviors that may have caused a yet undetected H.I.V. infection, such as intravenous drug use or unprotected sex with partners who do not regularly get...