Sutton first observed grasshoppers, to try to figure out how traits are passed from parent to offspring. He was very interested when he discovered that grasshopper body cells had 24 chromosomes or a diploid cell, but the grasshopper sex cells had 12 chromosomes, or a haploid cells. Sutton then created the chromosome theory of inheritance to explain his observations. The theory states that genes are carried from parents to their offspring on chromosomes.