Introduction: Microbiome in human reproduction.

The human microbiome has been termed the "second human genome" and data that has come about of late certainly makes it appear every bit as complex. The human body contains 10-fold more microbial cells than the human cells and accounts for 1%-3% of our total body mass. As we learn more about this symbiotic relationship, it appears this complex interaction occurs in nearly every part of the body, even those areas at one time considered to be sterile. Indeed, the microbiome in human reproduction has been investigated in terms of both the lower and upper reproductive tract and includes interactions even at the point of gametogenesis. What is all the more fascinating is that we have known about the importance of microbes for over 150 years, even before they existed in name. And now, with the assistance of an exciting technologic revolution which has pushed forward our understanding of the microbiome, we appear to stand on the precipice of a higher level of understanding of microbes, the biofilms they create, and their impact of health and disease in human reproduction.