TY - JOUR A1 - Newson, L. A1 - Postmes, T. A1 - Lea, S.E.G. A1 - Webley, P. T1 - Why are modern families small? Toward an evolutionary and cultural explanation for the demographic transition Y1 - 2005 DO - 10.1207/s15327957pspr0904_5 JF - Personality and Social Psychology Review VL - 9 IS - 4 ER -