Estrogen dominance can contribute to some cancers. However, it is important to realize that not all estrogens are the same and that there are different theories. One popular theory states that estrogen causes cells to replicate faster, increasing the production of cancerous cells. Another focuses on how estrogen is broken down and removed from the body. A third is how estrogen cannot fuel cancer in the presence of progesterone. A fourth reminds you that some estrogens are actually protective and anti-cell proliferative. So, what’s a person to think? All of the above are true, and of course chemical estrogens are by far the worst.