Boobs contain the female mamaliary gland, which begins to develop near the start of pubety. This is the part which produces milk (the acutal point of boobs). Unlike other mamals, human mamaliary glands are usually mounted on some fatty tissue, known as the boob. The amout of fatty tissue varies from woman to woman, and is not usually indicative of her milk producing ability. Anthrapologists are still unclear as to the purpose of the fatty deposit, but many men find it atractive.