In the last three years, comprehensive school-based clinics have proliferated throughout the United States: There are currently 138 clinics in 30 states and the District of Columbia, and at least 65 more are in the planning stage. Clinic programs differ widely in their organizational structure, operating costs, range of services and funding sources. Although some clinics are funded by private foundations, increasingly, programs are being initiated by local public health departments supported by state funds. Only 10-25 percent of all clinic visits are for family planning services. While all of the clinics provide counseling on family planning, most of the state-funded clinics either prohibit the use of funds for contraceptive supplies and abortion referral or allow grantees to decide what to do about the issue of pregnancy prevention. To date, no study has found that rates of sexual activity increase among students who participate in clinic programs. There is some evidence indicating that participation in school-based clinics may have a positive impact on contraceptive practice.