When living with a partner, you may share a significant percentage of the same microscopic organisms that affect your health. The human microbiome, which includes mainly bacteria, viruses, and fungi, consists of around 30% of the human body's resident microbes in the gut alone. This is not just the gut, but also the microbes in other parts of the body that may also be shared. Studies have found that living with your partner can influence the microbiome. Couples living together may share 13% to 30%, which is linked to lower risk of irritable bowel syndrome, cardiovascular diseases, and potentially high blood sugar. However, some of the bacterial species couples share can have different health outcomes, including those from the Ruminococcus family. A ten-second kiss can exchange up to 80 million bacteria, which couples actually share often.