Neonatal sex and birth-order effects on behaviors of mothers and temporary caretakers during bottle-feeding.

This study examined the effects of neonatal sex and birth order on maternal caretaking patterns for pre-attachment behaviors shown by mothers and instrumental behaviors seen in both mothers and temporary caretakers. Observational category scores were obtained for mothers of 20 newborn infants and for temporary caretakers observed in a 15 min bottle-feeding situation. A repeated measures analysis of variance design was used to partition categories into caretaking classifications and to evaluate the effects of infant sex and birth order. Significant main effects for caretaker (p less than .05) were obtained: six mother-high, pre-attachment categories, and seven mother-low, instrumental behavior categories. Maternal scores sensitive to infant sex and birth order were identified from Caretaker x Sex x Birth Order interactions (p less than .05). Birth order differences affected maternal behaviors directed toward sons more substantially than those directed toward daughters. Mothers held first-born sons upright in tactual contact with the trunk, whereas daughters were held supine on the lap and exposed to frequent maternal smiling.