Here are 31 interesting facts about breasts– one for each day of October, Breast Cancer Awareness Month:

1. The average woman in the U.S. wears a size 40 D bra; this equates to about 1.5 pounds per breast.
2. In most women, the left breast is usually slightly larger than the right. Very few women have perfectly symmetrical breasts. A slight difference in size between the right and left breast (up to 20 percent) is normal. Sudden changes are not, though, and are reason to talk to your doctor.
3. Breasts normally grow for about 2-4 years after a girl gets her first period.
4. Breast cancer ranks as the #2 cancer killing women, only behind lung cancer.
5. Men can get breast cancer as well; there will be an estimated 2,600 new cases of male breast cancer this year. A man’s lifetime risk of breast cancer is about 1 in 1,000. Filmmaker George Lucas is a breast cancer survivor.
6. Women can reduce their risk of breast cancer by watching their weight, exercising regularly, limiting alcohol intake and avoiding or limiting menopausal hormone therapy.
7. Breast cancer incidence in the U.S. varies greatly by state. The 3 states with the highest incidence of breast cancer are Massachusetts, Connecticut and New Hampshire.
8. States with the lowest incidence of breast cancer include Texas and New Mexico.
9. The International Agency for Research on Cancer has found evidence that shift work, particularly at night when it disturbs the body’s internal clock the most, might be linked to an increased risk of breast cancer.
10. In 2018, an estimated 266,120 women are expected to be diagnosed in women in the U.S., along with 63,960 new cases of non-invasive (in situ) breast cancer.
11. Famous women who have battled breast cancer include feminist Gloria Steinem, opera star Dawn Upshaw, former first lady Betty Ford, author Judy Blume, singers Sheryl Crow, Kylie Minogue, Olivia Newton-John and Melissa Etheridge, TV news hosts Hoda Kotb, Robin Roberts and Giuliana Rancic, Olympic figure skaters Dorothy Hamill and Peggy Fleming, Olympic gold metal cross country skier Kikkan Randall, businesswoman Carly Fiorina, and actresses Brigitte Bardot, Kathy Bates, Ann Jillian, Kate Jackson and Dihann Carroll.
12. Ancient Egyptians were the first to document the disease more than 3,500 years ago. Ancient writings on papyrus contain descriptions of conditions that are consistent with modern descriptions of breast cancer. One ancient Egyptian surgeon describes “bulging tumors” in the breast and states that “there is no cure.”
13. For 98 percent of the female population (those not at exceptionally high risk for breast cancer because of family history), it is recommended that annual mammograms be done starting at age 40.
14. The first radical mastectomy was performed in the late 1800s by William S. Halsted, a surgeon at Johns Hopkins and champion of newly discovered anesthetics.
15. Susan G. Komen was a young woman from Peoria, IL who was diagnosed with breast cancer in 1977 at the age of 33 and died from the disease three years later. Her younger sister, Nancy Goodman Brinker, who believed that Susan’s outcome might have been better if patients knew more about cancer and its treatment, promised her sister that she would do everything she could to end breast cancer, and founded the Susan G. Komen Breast Cancer Foundation in 1982.
16. Although there’s been a lot of confusion recently about how and when to be screened for breast cancer, one thing’s for sure: early detection is critical. When breast cancer is detected early, survival rates jump.  The American Cancer Society advises that a clinical breast exam (done by a doctor) be done every three years beginning at age 30. Annual mammograms should begin at age 40. More intensive screening is advisable for those at high risk due to family history or other risk factors. Between clinical exams, women should self-examine every month. Click here for how to do a breast self-exam.
17. In 1998, President Clinton signed into law the “Women’s Health and Cancer Rights Act,” which ensures that a woman’s health plan that covers mastectomy surgery must cover all stages of reconstruction to both the breast with cancer and the breast without cancer, if desired.
18. About 12 percent (one in eight women) of U.S. women will develop invasive breast cancer during their lifetime.
19. Physicians determine the stage of a cancer at the time of diagnosis in order to create a treatment plan and determine the prognosis of a patient’s condition.  The Stage is described as a range from pre-cancer (DCIS) to Stage IV (metastatic cancer—that which has spread to other areas of the body.
20. There are several medical terms for breast: mamm-o as in mammography; mast-o as in mastectomy; maz-o as in “amazon, ” which means “without a breast,” like the Amazon female warriors of Brazil who legendarily cut off their breasts for improved ability to shoot their bows.
21. Both men (1 in 18) and women (1 in 50) may have one or more extra nipples.  This is called Polythelia, and is often mistaken as a mole.  Any breast tissue, whether it appears in the standard location or elsewhere along the “milk line” is vulnerable to the same diseases that can affect typical breast tissue.
22. Breastfeeding of infants is on the rise in the U.S., increasing by an average of 2 percentage points per year, according to the latest CDC statistics. Breastfeeding is most prevalent in the West, with Idaho, Washington, Oregon and California containing the largest percentage of mothers nursing for the highest number of months, and southern states Mississippi, Louisiana and West Virginia with the lowest percentage.
23. There are many different types of breast cancer.  Certain drugs which “cure” one type of cancer are not effective with others.
24. Lumpectomy is the removal of part of the breast involved with cancer, along with a margin, or part of surrounding tissue.  A long term series of trials conducted by the NSABP determined that long term, outcome was in women with similar stage of disease when treated by mastectomy versus lumpectomy and radiation treatment.
25. An estimated 85 percent of breast cancers occur in women who have no family history of the disease.
26. Survival rates from breast cancer have been steadily improving. According to the National Cancer Institute’s SEER (Surveillance Epidemiology and End Results), the rate of death due to breast cancer has decreased by about 2 percentage points since 1990.
27. The breast lies on top of the pectoral, or chest muscles. Women’s breasts are comprised of skin, nipples, fatty tissue and a special network of glands that produce milk. The amount of fat determines the size of the breast. The milk-producing part of the breast is organized into 15 to 20 sections called lobes.
28. Breast Augmentation with implants—filled either with silicone or saline—is still the most popular plastic surgery procedure for women.  In 2013 the American Society for Plastic Surgery reported almost 300,000 augmentations with implants.  However, the number of breast “lifts” or mammoplasty procedures (women trying to improve the looks of their breasts without using an implant) is growing at twice the rate of implant procedures.
29. Breasts come in lots of different shapes and sizes. Professionals working in the Plastic/Reconstructive Surgery area have coined some interesting terms for some of the most common breast deformities: Tubular or “tube sock” breasts often result from breast-feeding; flat tires are the “saggy” breasts that look deflated with age or lots of nursing; “Snoopy” breasts result from a genetic condition.
30. Although there’s no such thing as perfection, some of the most famous bustlines have, not surprisingly, come from Hollywood. Jayne Mansfield, Sophia Loren, Marilyn Monroe…and many more since then (which, increasingly, have been surgically enhanced!)
31. Actress, director and humanitarian Angelina Jolie stunned the world in 2013 by announcing in a New York Times op-ed that she had undergone prophylactic mastectomies to reduce her risk of developing breast cancer.  Her admission that she was BRCA positive led to a doubling of the women tested for this genetic defect in the following 6 months.