This study investigated pregnant teenagers' knowledge about infant development during the period of their pregnancy. The sample consisted of 98 teenagers between 14 and 19 years old who were pregnant with their first child; all were planning to keep their babies. The group was approximately 50% black and 50% white, 50% middle class and 50% working class in composition. Most of the subjects (70%) still lived with their parents. A prenatal interview was conducted in each subject's home during her last trimester. Three instruments were used. The first required the subject to rank order six areas in which she felt she needed more information: prenatal care, health and nutrition, basic caregiving and safety, perceptual and motor development, social development, and cognitive development. The second instrument used a card sorting technique to measure the subject's expectations regarding the temporal emergence of particular needs and abilities of infants and toddlers. The third instrument consisted of 16 videoclips of a range of appropriate and inappropriate infant activities and mother-infant interactions. The subject was asked to explain what the baby was doing and to say whether she would act the same way as the filmed mother or differently. Additional questions were asked about the subject's own development and future plans. The general finding was that teenagers expect too little, too late with respect to the cognitive and social development of babies. (Author/SS)