The human microbiome - the totality of all microorganisms that inhabit the human body - has been increasingly in the focus of research for years. Scientists now agree that this microbial ecosystem is essential for a stable and functioning immune system and is therefore crucial for our health. But how and when does the microbiome actually develop, and how can we optimally promote the presence of beneficial microbes within it? The microbiome consists of trillions of microorganisms that live on and in us - bacteria, fungi, and viruses. These microbes reside on our skin, in the digestive tract, in the urogenital area, in the mouth, in the nose, in the lungs, and in women, in the vagina. During birth, the mother's microbiome is transferred to the baby, kickstarting its immune system. Artificial birth processes such as cesarean sections can influence this process.