Although the exact cause of endometriosis is unknown there are a number of factors which are believed to influence the development of the disease:

• Heredity.  Although there is no identifiable gene which passes endo from mother to child you chance of developing endometriosis is seven times higher if your mother or sisters have it.
• Immune system function. People with endometriosis may have lower functioning immune systems that have trouble eliminating stray endometrial cells. 
• Dioxin exposure. Some research suggests a link between the exposure to dioxin (TCCD), a toxic chemical found in weed killers, and the development of endometriosis.

While many of us with endometriosis live with debilitating symptoms, others have the disease without knowing it. Paradoxically, there does not seem to be any relation between the severity of the symptoms and the extent of the disease. The most common symptoms are:

• Menstrual pain: Pain in the lower abdomen that begins a day or two before you period starts and continues through to the end is a common sign  of endometriosis. Some notice lower back aches and pain during urination and bowel movement, especially during their periods.
• Painful sexual intercourse: Pressure on the vagina and cervix causes severe pain for some people.
• Abnormal bleeding: Heavy periods, irregular bleeding, and spotting are common features of endometriosis but these can also be signs of some gynaecological cancers. If you have these symptoms go and get them checked out.
• Infertility: There is a strong association between endometriosis and infertility, although the reasons for this have not been fully explained. It is thought that the build up of scar tissue and adhesions blocks the fallopian tubes and prevents the ovaries from releasing eggs. Endometriosis may also affect fertility by causing hormonal irregularities and a higher rate of early miscarriage.