The main aim of the FAMILY study is to identify the environmental, genetic, and biochemical factors important in the development of obesity, cardiovascular risk factors, and atherosclerosis in childhood. Over 850 pregnant women were recruited during their third trimester of pregnancy from three hospitals in the Hamilton region, Canada from 2004 to 2009. Over 900 children of these women, 530 fathers and 260 full older siblings are also included in the study. Mothers, fathers and siblings completed baseline assessment at recruitment and children were assessed at birth from 2005 to 2009. All participants were followed up every 1 to 5 years until the child was 10 years old.