Some types of hormone replacement therapy carry very high risks (increased risk of heart attack, stroke, breast cancer, etc) and some do not. I’m including a link to the Wikipedia article about HRT. It does a good job of generally explaining the issues without a lot of scientific mumbo jumbo.

and by the way estrogen replacement by itself causes a high risk for breast cancer, estrogen – progesterone treatments are best because the progesterone dereases the risk

Journal of American Medical Association (17 July, 2002)
Risks and benefits of oestrogen plus progesterone hormone replacement therapy in 16,608 healthy post-menopausal women to assess the long term health benefits and risks (JAMA. 2002; 288(3):321-333).
The trial was to run for 10 years but was stopped shortly after 5 years as the overall health risks exceeded the benefits. Increased risks were seen for coronary heart disease, breast cancer and stroke. There was a reduction in risk for colorectal cancer, endometrial cancer and hip fractures.
As many of these increased risk factors are seen as reasons for women to be prescribed HRT, it is expected that these latest results showing HRT resulted in not a prevention but an increased risk for these diseases, will greatly increase the demand for natural alternatives to HRT.

Using Hormone Replacement Therapy (HRT) to relieve menopausal symptoms was becoming popular as early as the 1960s. Widespread interest in HRT was likely spurred by the 1966 publication of gynaecologist Robert Wilson’s book Feminine Forever. In his book Wilson glorified oestrogen as a proverbial “fountain of youth”. By the mid 1970s American physicians were writing more than 30 million prescriptions a year for the hormone, and approximately half of all menopausal women were using HRT for a median duration of five years.
Over the past 25 years more than 50 studies have examined the link between HRT and breast cancer. Increasingly results confirm that long-term use (over two years) of hormone therapy may result in an increased risk of breast cancer. This increased risk becomes more significant for women who are at high risk for the disease, among them women with a prior history of breast malignancies and women with a strong family history of breast cancer.