This term applies to having condom-less sex with someone with the same HIV status as your own. Some HIV-positive people choose to sero-sort with other people they know are also HIV-positive as a way to alleviate the concern, and reduce the risk, of passing on HIV to HIV-negative people, or to people who do not know their HIV status. HIV-negative people (who regularly test and know their HIV-status) sometimes also serosort, but this is riskier than when HIV-positive people serosort, because some people do not know their HIV status (because they do not regularly test for HIV) and therefore assume they are HIV-negative. Either way, not using condoms increases the risk on passing on or getting other sexually transmitted infections (STIs) and sexually acquired Hepatitis C. It is also possible for HIV-positive people to pass on their strain of HIV to another HIV-positive person – called ‘Superinfection’- but this is highly controversial since it is unknown how common (likely) this might be or how greatly it may impact on HIV antiretroviral treatment outcomes (if a new resistance was acquired). Nonetheless, serosorting can be an effective Risk Reduction Strategy when the other person’s HIV-status is accurate from confirmed testing for HIV. Effective serosorting does not work if you try to guess, or assume, another person’s HIV-status.