Summarize the following:
Although being a woman is the main risk factor developing breast cancer, there are also a number of other factors that increase the likelihood that you could develop breast cancer, including   Age: Risk increase with age. Most people who have breast cancer are over 45 years old. Once you reach the age of 50, your risk increases ten-fold for each decade beyond 50.  Menstruation: If you started menstruating before you were 12 years old, or entered menopause when you were older than 55, your risk is slightly increased. In both cases, the risk is higher because of the increased ovulation cycles.  Pregnancy: An early pregnancy or multiple pregnancies can both reduce your risk. Having no children or getting pregnant after the age of 40 increases your risk of developing breast cancer.  Hormone replacement therapy (HRT): Current or previous use for more than 10 years can increase the risk for breast cancer. Obesity, smoking, alcohol use, and shift work are all risk factors for breast cancer.  Whether someone is overweight or obese is determined by using the body mass index (BMI). BMI is a person's weight in kilograms (kg) divided by the square of the person's height in meters (m). A BMI of 25-29.9 is considered overweight, while a BMI greater than 30 is considered obese. A BMI greater than 30 is considered a risk factor for developing breast cancer, since fat cells secrete estrogen, which feeds many breast cancers. There is also some recent evidence that long-term heavy smoking correlates with a higher risk of breast cancer. The risk is especially high among certain groups of smokers, such as women who began smoking before they had their first child. Research is still being conducted to determine the exact relationship between smoking and breast cancer. Alcohol has also been linked to increased risk of developing breast cancer. The risk increases the more you drink alcohol. Women who consume between two and five drinks every day have a 1.5x higher risk than women who don't drink. Recent research has suggested that women who work night shifts (such as nurses) may have an increased risk of breast cancer due to changes in melatonin levels. Further research is needed, however, before these findings will be considered conclusive. There are also risk factors related specifically to you, your family history, and your genetics, including:   Personal medical history: If you have had a previous diagnosis of breast cancer, you are three to four times as likely to develop a new cancer in the same or opposite breast.  Family history: You are more likely to develop breast cancer if one or more close blood relatives in your family have had breast, ovarian, uterine or colon cancer. Your risk is doubled if you have a first-degree relative (sister, mother, daughter) with the disease. Having two first-degree relatives triples your risk. Genes: Genetic defects found on BRCA1 and BRCA 2 can dramatically increase your risk of developing breast cancer. You can opt to find out if you have these genes by contacting a genome mapping service. In general, approximately 5-10% of cases are related to heredity. The majority of women don't exhibit any of the above and are no more or less likely to breast cancer than anyone else. As a result it is imperative that women practice the above guidelines regarding breast health and that they notify their primary care physicians if they notice any changes in their breast tissue.

Summary:
Be aware of the basic risk factors for breast cancer. Be aware that your lifestyle can affect your breast cancer risk. Know your personal and family medical history. Be aware that most women diagnosed with breast cancer have NO risk factors.