1. Breasts, and their production of milk for offspring, define all mammals, but we humans are the only primates whose boobs get bigger at puberty and stay that way. Lucky us.
2. The breast is basically a modified sweat gland made up of fatty, glandular, and fibrous tissue. A handful of 15-20 milk glands sit underneath the nipple ready to produce milk.
3. One breast alone can produce 450 mL of milk a day during lactation. That means a pair of breasts can produce just shy of a litre of milk each day.
4. According to the latest Canadian Community Health Survey, in 2003, 85 percent of mothers breastfeed, but the majority don’t stick to it for very long. About one fifth quit after the first month, and just under half last for six months.
5. Women’s breasts seesaw in size over their cycle with the ebb and flow of hormones like progesterone. One study found that breast volume ballooned up to 40 percent in the week prior to menstruation.
6. Turns out 90 million women can be wrong – at least when it comes to their bras. A survey published by Wacoal in 2005 found that eight out of ten American women wear the wrong size bra.
7. To the frustration of the undergarment industry, 59 percent of women confirm that their bras never seem to fit exactly right.
8. The most common sin? Overestimating band size while underestimating cup size. No wonder bras cause back, shoulder or neck pain in three out of five women.
9. Damned if you do, damned if you don’t: One Japanese study found that wearing bras made boobs sag more, not less. Their theory is that the Cooper’s ligaments, which are the boob’s built-in support system, atrophy when breasts are held up by a bra.
10. Boobs are swelling the world over, thanks to rising obesity and the number of women taking birth-control pills. According to Marks & Spencer, the average U.K. breast size has swelled from 34B to 36C in five years.
11. These days, one-third of American women wear a D cup or larger. Sales of DD bras and larger have surged 24 percent in the past year.
12. A pair of D-cup breasts can weigh between 15 and 23 pounds, the equivalent of carrying around a six-month old baby boy.
13. Reason number one to invest in a good sports bra: small breasts can move up and down more than three inches when you jog, and large ones can bounce out of their bras entirely.
14. Extra-large bazooms aren’t just a burden – without a supportive bra, they may be a health hazard. Thin straps can dig into the nerves that run down your arm, causing numbness in the little finger. In some cases, big boobs can slap against your chest with enough force to break your collarbone.
15. Plastic surgeons have charted the golden ratios of the breast – the average ratio of nipple to areola and areola to breast distance hovers around one to three.
16. Sex researcher Alfred Kinsey estimated that breasts and nipples are erotically sensitive in half of all women. But a more recent study found that nipple stimulation turned 81.5 percent of university-aged women on.
17. The nipple expands during sexual arousal – it sticks out by up to 1 cm and widens a bit, too – only to rapidly deflate after orgasm into crinkled skin. There’s something women can’t fake.
18. If most women’s nipples are outies, then three out of every 100 nipples are innies, or inverted nipples, according to one survey back in 1999.
19. When it comes to breast size, we all seem to envy one another’s endowments. Smaller-breasted women are less satisfied with their breasts than larger breasted ones, but the reigning contradiction comes from incompatible body ideals: we want a slender body with large breasts – a tall order given that breast size is correlated to body fat.
20. Twelve percent of British men find breasts the most sexually attractive female body part. And 55 percent reported that they favoured “modest-sized breasts.”
21. But then does it really matter what men desire, since we get it wrong anyway? According to one survey, women consistently overestimate the breast size men actually prefer.
22. Over the past 50 years, Playboy centerfolds have become taller and thinner with smaller breasts, replacing the curvy silhouette with a more androgynous one. Think Marilyn Monroe vs. Eva Herzigova, who sent Wonderbra sales soaring in 1994 with her reported 36B cup size.
23. A survey of American women done by Vagisil Women’s Health Center in 2003 found that 48 percent of women believed breast cancer was the number one killer of their sex. It’s not. Heart disease caused six times more deaths than breast cancer did in 2003.
24. Breast cancer is, however, the most common cancer plaguing women worldwide. In Canada, 22,000 women, or one in nine, are diagnosed each year.
25. The incidence of breast cancer has risen here by 30 percent between 1969 and 1999, but mortality has dropped by 25 percent since 1986.
26. One in 27 Canadian women will die of breast cancer.
27. Your antiperspirant is deadly only to your B.O. Ignore all those scary emails – a study at the U.S National Cancer Institute found no correlation between underarm grooming regimes and breast cancer.
28. Many people think bras increase the risk of cancer by constricting the flow of lymph fluid, but there is no evidence that this is true.
29. Breast augmentation is the most popular cosmetic surgery for women in the U.S. But, in 2006, for every 12 women who got implants, one had them removed. That same year, for about every three American women who got implants, one had breast reduction surgery.
30. A recent study tracked 3,527 Swedish women who had implants and found that they were three times more likely to die from suicide.