Additional Study Information: We are recruiting boys between 3-9 years old and girls between 3-8 years old to participate in a research study. Children who would like to participate must be healthy and not showing signs of puberty. The goal of the study is to understand the relationship between early body development, metabolism (sugars and fats processing), and the saliva microbiome (bacteria that normally live inside the body). The study is performed in the morning after an overnight fast and may be completed in less than 2 hours. The study includes the following: Physical exam and body measurements, blood test, and saliva collection. All studies are safe and are approved for children. The study takes place at Columbia University Irving Medical Center in New York City. We will send a summary of the available results to the participating childs pediatrician at the end of the study. There will be compensation for your child's time.