This paper discusses a series of three studies investigating the influence of infants' characteristics and signaling behavior on parents. Videotapes of either smiling/cooing/gurgling or crying infants were used to elicit parents' physiological and affective responses. Measured physiological responses included skin conductance, heart rate, and systolic and diastolic blood pressure. A 10-item mood adjective checklist, a demographic information sheet and the Infant Temperament Questionnaire were completed by parents after the videotape presentation. It was found that images of crying infants elicited a pattern of autonomic arousal usually associated with response to an aversive stimulus. Reported emotional responses to the crying infant were consistently aversive. A crying infant identified as premature was perceived as more aversive than a full-term infant. Mothers of premature infants rated themselves significantly more happy, attentive, and alert than mothers of full-term infants. However, they found the image of the premature infant less pleasant than did mothers of full-term infants. Mothers of premature infants also were more physiologically aroused when viewing the premature infant than were mothers of full-term infants. Insofar as premature infants are more likely to be abused than those born full-term, the findings that premature infants increased autonomic arousal or are perceived as especially aversive when crying may have important implications for the understanding of child abuse. (Author/RH)