A Cedar Rapids teen has been charged with sex abuse based on allegations he committed a sex act on a 10-year-old boy he was baby-sitting.Espoir Mukula, 16, is accused of second-degree sex abuse, a Class B felony punishable by up to 25 years in prison. The 10-year-old boy told his parents Mukula had committed a sex act on him April 27 when Mukula was baby-sitting the boy, court records state.