The most obvious problem associated with abnormal cell division is cancer. Cancer is defined as uncontrolled cell division whereby the natural mechanisms that start and stop normal cell division are damaged and the cells constantly divide. These cancerous cells grow and form tumors. If these tumors metastasize, or spread to other parts of the body, then this becomes a very dangerous health situation. Other problems that can occur as a result of cell division involve cells being produced with an improper number of chromosomes. Chromosomal abnormalities in sexual cells can lead to birth defects like Down Syndrome.