Research has now shown that boron supplementation in postmenopausal women doubles blood level of most active form of o-estrogen, 17-beta oestradiol, to the level found in women on oestrogen replacement therapy. Equally, the blood levels of testosterone more than doubled (7).
With HRT there is a higher risk of breast or endometrial cancer which is not known to happen with hormones produced by the body as with borax supplementation.  Some women get premenstrual problems because oestrogen levels are too high & progesterone too low, & therefore may be afraid of using boron. However, I (author) found no evidence that boron raises o-estrogen above normal healthy levels. Boron may balance levels of sex hormones similar to the action of maca root powder. 
Maca acts on the pituitary gland not only to increase & balance our sex hormones & seems to stimulate our own progesterone production as needed.  (However, the CAUTION is correct & excess can contribute to or trigger breast or other hormonal problems, at least for those with a family history of such issues)...
I believe that cancer can usually be controlled with long-term antimicrobial therapy.
Therefore I (author) would use boron as well as maca. (Final NOTE: spiritual worldview may not be Judeo-Christian.)