Ho, H., Plomin, R., & DeFries, J. C. (1979). Selective placement in adoption. Social Biology, 26, 1-6.

Using data from the adoption agency files for 206 "first" adoptions, we found little evidence for selective placement based on demographic characteristics of the parents or on infant characteristics such as gender, gestational maturity, APGAR scores, time in hospital, and time in foster care.