Well, those herbs are safe ONLY when you use them the way they were meant to be used. But when you start increasing your estrogen dramatically by increasing certain herbs, then, yes, your chances of breast cancer increase. ANYTHING that raises estrogen levels in an unnatural way can cause breast or uterine or ovarian cancer, any kind of "female related" cancer. This includes the use of birth control pills and hormone replacement therapy, this is a proven, scientific fact. And, yes, the way people are using these herbs is very unnatural, even if they are herbs (the people using them for breast enlargement, not hormone balance). This can also cause uterine fibroids, which are cyst-like tumors, which aren't cancerous, but can make your stomach larger and uncomfortable or can impede fertility. The high levels of estrogen can also lead to ovarian cysts, which cause more problems than you'd care to have, including, possibly, infertility. Yes, it has the potential of causing ANY type of "female related" cysts, including breast cysts and, yes, higher than natural levels of estrogen FEED breast cancer cells which can lead straight to breast cancer. Anything that messes with your hormone levels the way some people are using these herbs can be a danger to your health and your fertility. They can also affect your moods negatively and increase PMS drastically (REAL attractive!), and they can diminish your sex drive, because too high levels of estrogen decrease sex drive, although there are some herbs that also affect other hormones that increase sex drive, but most of the estrogen increasing herbs can decrease the sex drive at the amounts they are using them. So what is so sexy about a woman who has larger breasts but a low sex drive? Besides, most women don't grow larger breasts with these herbs, so you can get all the bad effects without the goal you were after, that would completely suck, huh? Plus, some women are using them while using birth control pills, which is a double major risk, no matter who or what web site tells them that it's OK. Hormones should not be messed with in such an unnatural way. And there's nothing natural at all about the high levels of herbs being used by some of these people. Herbs are powerful natural drugs, very good to use, but NOT OVERUSE. Good health should be more important to women than bigger breasts, there's nothing even remotely sexy, beautiful or confident about what these women are doing to their bodies. It doesn't make them bad people at all, just people making bad choices and being bad examples for younger girls. But, yes, there is a way to safely take them to balance your hormones, but you have to do some good research. Do a search for [removed] But I hope that helps you make a better decision. Good luck. :)