Birthmarks are colored marks on the skin that are present at birth or appear shortly after. They can vary in size, shape, and color, ranging from light brown to dark red or even blue. Birthmarks are generally harmless and can be classified into two main types: vascular birthmarks, which are caused by blood vessels, and pigmented birthmarks, which are made up of clusters of pigment cells. Most birthmarks do not require treatment and may fade or change over time. However, some may need medical attention if they grow, change color, or cause discomfort. Parents should consult a healthcare professional if they have concerns about their child's birthmark.