The authors undertook the present study to determine whether under ecologically valid, low-stress conditions, female and male neonates could be differentiated on cuddliness. Sixteen female and 15 male neonates were videotaped interacting briefly with both a female and a male adult who were blind to the sex of the neonate. Raters coded degree of cuddliness and activity level. Results showed that raters could discriminate the sex of the neonate on the basis of degree of cuddliness. Discussion focuses on the importance of theoretical and methodological considerations in assessing sex differences in behavioral characteristics of neonates.