The purpose of the study of two sets of infant twins, where one infant of each set was severely handicapped, was to investigate the effect of a handicapping condition on mother-infant interactions and to investigate the conditions under which coordinated attention to an object and a person is demonstrated. This study provided a unique opportunity to make across-mother and within-mother comparisons of mother-infant interactions with fraternal twins. Microanalysis of several aspects of mother-infant free-play sessions showed that handicapped infants emitted fewer object-directed behaviors, had fewer instances in which their leads were followed, and spent relatively little time in joint attention with mother. The data also suggested that repetitive sequences with an object may be an important context in which coordinated attention is demonstrated. (Author/CL)