Description:This project investigated the effect of a woman's genetic composition on the ability of various microbes to colonize and/or infect the genital tract. The study was carried out by comparing and quantifying the microbial populations inhabiting the vaginas of monozygotic (MZ) and dizygotic (DZ) twins in the Mid Atlantic Twin Registry (MATR). The study also explored the relationship between the microbiomes of the vagina, mouth and GI tract and evaluated the effects of numerous other factors (e.g. pregnancy, menopause, infectious disease) on vaginal microbial communities.