Key points are not available for this paper at this time.
Peter La Freniere, F. F. Strayer, Roger Gauthier, The Emergence of Same-Sex Affiliative Preferences among Preschool Peers: A Developmental/Ethological Perspective, Child Development, Vol. 55, No. 5 (Oct., 1984), pp. 1958-1965
Freniere et al. (Mon,) studied this question.