Ureaplasma is a group of tiny bacteria commonly found in the urogenital tracts of both men and women. They form part of the normal genital flora but can cause infections under certain conditions. Ureaplasma species, especially Ureaplasma urealyticum and Ureaplasma parvum, are linked to conditions such as urethritis, pelvic inflammatory disease (PID), and infertility. Although they can be sexually transmitted, they are not always strictly classified as STIs.