Many states require a health or wellness course in order to graduate. The class typically covers basic anatomy, nutrition, first aid, sexual education, and how to make responsible decisions regarding illegal drugs, tobacco, and alcohol. In some places, contraception is not allowed to be taught for religious reasons. In some places, the health and physical education class are combined into one class or are offered in alternate semesters. In some private schools, such as Catholic schools, theology is required before a student graduates. Two years of physical education (usually referred to as "gym," "PE" or "phys ed" by students) is commonly required, although some states and school districts require that all students take Physical Education every semester.