The tendency of an only son and youngest child get a different upbringing from parents and other family members will form a specific behavior of each child. Attention considerable affection only child obtained only from the father and mother so that he tends to further develop lekatnya behavior than younger son who get more attention, affection of father, mother and older brothers. This research is quantitative research that aims to determine the behavior of different bonding between child and youngest child. With variables (I) is an only child and youngest son, variable (2) is a behavior closely. Research subjects in this study were kindergarten students Alhidayah I & II Sub Udanawu Blitar district who have a mother does not work, status as an only child and youngest child aged 3-6 years and 56 children. The spread of bonding behavior scale was conducted on 13-15 April 2006. Data collection method used in this study are Likert scale method, while the data obtained were\ud
analyzed by t test (t-Test). The result of t test analysis (t-Test) concluded there are differences in maternal behavior of significant bonding between child and youngest child (t = 2.263 <Sig = 0.050), ie a single child has a level higher bonding behavior (X1 = 130.50 ) than younger children (X2 = 123.54). It is recommended to women who have a single child to give love and attention to their children that are not excessive and train children to attachment relationships to others such as: father, grandfather, grandmother and caregiver if there is
