The study was extended through January, 2008 to show compelling evidence for a haplotype in the 5' region of the Leptin gene (p<0.00005) influencing BMI among men in the sample. The study will further demonstrate that the responsible gene in this region is not Leptin. SNP and haplotype association studies implicate three strong candidate loci and other loci also warrant additional study. The study will confirm SNP association in an independent study of 200 families showing linkage to the same position (from Dr. R. Arlen Price's group). Those loci with confirmed association will be further characterized by sequencing, genotyping new polymorphisms, and gene expression studies to identify the responsible genes.