Balding or hair loss is the sudden or gradual loss of hair, typically from the scalp. Though it can affect both sexes, it is far more common in men than women. A number of factors are believed to contribute to hair loss, including genetics as well as the death or hair follicles, or disorders within the hair follicles. It is sometimes also a side effect of certain illnesses or medications, particularly chemotherapy drugs used to treat cancer. Treatment options depend on the cause of the hair loss, but include hair transplantation, laser hair surgery, and stimulation of the hair follicles to induce regrown hair.