Genes provide all of the instructions for how your body works. In total, we all have between 20,000 and 25,000 genes. All of the genes together are called your genome. Your genome is like a recipe book where each gene is a recipe.

Although we all have the same basic recipe book, we all have minor differences within our recipes (our genes) that make us unique (taller, shorter, brown hair, blond hair). In addition to how we look, these differences affect our health including what diseases we get and how we respond to medication.