The study, involving 15 nonhandicapped and 15 handicapped infants, investigated parental estimates of infant developmental functioning as a function of parental attitudes. Examined was the relationship between source of evaluation (mother, father, diagnostician), infant temperament category, and factors of maternal attitude (such as appropriate vs. inappropriate control of child's aggression). Among findings were that all three sources of evaluation agreed on the relative order of infants by mental age; the childrearing attitudes of mothers of handicapped infants were more inappropriate than the attitudes of mothers of nonhandicapped children; the maternal and paternal reports of all Ss' capabilities yielded significant underestimation of infants' mental ages when compared to diagnostic evaluation; and that infant temperament did not differentially influence parental perceptions of competencies. (SW)