Which things cause breast cancer and how can i reduce my chance of getting it?

Unknown: There are some increased breast cancer risks associated with obesity, hormone medication use, early age at first menstruation, late age at first childbirth, etc. Only about 15% of breast cancers occur because of genetic inheritance. See this site with more information: http://media.Komen.Org/breastcancer101tool/english/video-player.Html#kbc_01_01.