The principal objective of the U.S. family planning program is to prevent unwanted and mistimed births. As unwanted fertility has declined among married couples, out-of-wedlock births have continued to increase- especially to teenagers; and the overwhelming preponderance of such births are not intended. Thus, unwed teenagers, while accounting for less than five percent of total births in 1969, contributed eight percent of the unintended fertility in that year - nearly a twofold difference. Application of findings from the Johns Hopkins study of adolescent sexuality, contraception and pregnancy to U.S. census and vital data indicates that 1.4-2.3 million never-married young women aged 15-19 are in need of contraceptive services: and 1.3-2.2 million (representing15-25 percent of all never-married 15-19-years-olds) need services from organized programs. The maximum total need estimate of 2.3 million is strikingly close to the nationalestimate published by Joy G. Dryfoos, using a somewhat different methodology and definitions, that a total of 2.2 million teenager are in need of services. From various family planning data systems it is estimated that about 460,000 never-married teenager wereserved by organized family planning programs in 1972. This represents from one-fifth toone-third of the need for services from organized programs among this groups. Thus, most teenagers in need of services from organized family planning programs currently are notreceiving them.