It has been well accepted that effective programs for prevention of adolescent pregnancy should involve adolescent women and their partners. Using data from certificates of live births in Taichung County, Taiwan, in 1994, the demographic characteristics of fathers whose infants were bent to adolescent women were compared with a matched group fathers whose infants were born to women aged greater than or equal to 20 years. Most of the fathers of infants born to adolescent women were adults: 57% of the fathers of infants born to women aged less than or equal to 15 years were: greater than or equal to 30 years of age. Fathers of infants born to adolescent women had a lower educational level than that of matched fathers. These demographic characteristics of fathers should be carefully interpreted and taken into consideration in developing intervention programs. (C) Society for Adolescent Medicine, 1999.