Genital colonization by Mycoplasma genitalium (M. genit.) and Ureaplasma urealyticum (U. ureal.) is common. In the vast majority of cases, however, these do not cause symptoms; therefore, neither pathogen is sought in persons without symptoms.

M. genit. can cause urethritis, especially in men who have sex with men. However, these are much less frequently caused by M. genit. than by chlamydia and gonorrhea.

In women, M. genit. can cause inflammation of the cervix, but this is more often caused by chlamydia, especially in young women.

U. urealyt. is only in exceptional cases causative for diseases in the genital area.