There is an epidemic of big breasts in the western world. "Daily Mail" signals that the average bra size has boomed from a 34B to 36C in 10 years only. Breast implants are easy to blame, but they cannot explain this massive flood. The reasons are complex.

One factor would be the epidemics of obesity. In US, 60 % of the adults are overweight, and half of them are considered obese.

"Fat is laid down on breasts as much as thighs or bottoms, and we are in an epidemic of obesity," nutritionist Marilyn Glenville told Daily Mail.

The hormone replacement therapy (HRT) discharges high amounts of estrogen into the organism and it is aimed to combat menopause symptoms. The female breast cells contain, on their surface, proteins called estrogen receptors. These proteins are stimulated by the estrogen and cause the cell to divide, resulting increased mammary tissue. HRT is known to increase breast size, but the way it does it is a dangerous one, as in 70 % of the cases breast cancer is triggered by estrogens.

"The more exposure we have, the more likely we are to get breast cancer," said Glenville.

"If men took estrogen as they used to in the early days of treating prostate cancer, they developed noticeably larger breasts," consultant gynecologist Peter Bowen-Simpkins, medical director of the London Women's Clinic and spokesman for the Royal College of Obstetricians and Gynecologists told "Daily Mail".

"Our daughters are reaching puberty earlier - sometimes as young as eight. This means they will have much more exposure to estrogen in their lifetimes. Women are also having fewer children so the body is exposed to higher levels of estrogen in the long term, as during pregnancy and breastfeeding estrogen levels in the body are lower," explained Glenville.

But more concerning are the estrogen-mimicking chemicals (xenoestrogens) that enter in our bodies involuntarily, through contamination with pesticides, plastics, food or cosmetics. Plastics known to contain xenoestrogens are those based on Bisphenol A (BPA). Aluminum salts from antiperspirants can act like estrogen as well. Even lavender or tea tree oils contain estrogen-mimicking chemicals.

"Many products, from lipsticks to tampons to spermicides, contain xenoestrogens - and we are applying them directly to our bodies," added Glenville.

Big boobs have also been connected to increased alcohol consumption.

"It has a toxic effect on liver function. This means estrogen and other hormones can end up being recirculated around the body and perhaps reabsorbed instead of being broken down in the liver, if that organ has been damaged by too much alcohol," said Gleenville.

Two positive factors have been signaled by Daily Mail as connected to larger breasts: bigger pectoral muscles due to exercising and improved child nutrition.