Estrogen is produced in the female body in order to help control the reproductive system in the female body. There are three types and they are called estriol, estradiol and estrone. Sometimes, people will need more estrogen in order to control parts of their reproductive system. This would come in the form of medication.
If you have every heard of hormonal therapy, this usually involves estrogen. It actually has quite a few functions including thickening the wall of the vagina, helps increase your metabolism, and helps with formation of the bones. A carcinogen is something that causes cancer. So, it may see strange that estrogen is a carcinogen, but it is because it does cause cancer but it also helps.