When people practice Serosorting they are choosing a sexual partner who shares the same HIV status. An example of serosorting practice would see a HIV positive person showing a preference for engaging sexually with another HIV positive person, and the same would apply to a HIV negative person engaging with a HIV negative partner by choice.
Serosorting is thought to reduce the risk of acquiring or transmitting HIV as partners share the same HIV status (negative or positive).
The key to serosorting is you have to actually know both your HIV status and your partners’ HIV status. Serosorting also offers no protection from other STIs. HIV infections happen between people who think they are both negative but one person isn’t.