Why some people have six finger in their hands?

The presence of a sixth finger, a condition known as polydactyly, can occur due to genetic factors, often inherited as an autosomal dominant trait. It results from an anomaly during fetal development, where the process of digit formation does not occur normally. Polydactyly can vary in appearance, ranging from a fully formed extra digit to a small nub. While it is usually harmless, some individuals may choose to have the extra finger surgically removed for cosmetic or functional reasons.