The number of reported cases is split rather evenly between men and women, although schizophrenia tends to present itself at different ages for the two sexes. Onset of the disorder tends to occur earlier for men—usually in the late teens or early 20s—compared to women, who generally begin to show signs of trouble in their 20s or early 30s. An identical twin of someone with schizophrenia has about a 40 percent to 65 percent chance of developing the illness. Interestingly, researchers have found there is a further heightened risk for a female identical twin to develop schizophrenia if her twin has the illness. Women tend to have a less severe form of the disorder and respond better to treatment.