Sorry to disagree, but using PM alone can have serious feminizing effects, WITHOUT the use of antiandrogens. Take a look at my pics on the picture page in this section. I stopped using any kind of SP or Pygeum back in 2010. There are other regular contributors to this section that also don't use SP or any antiandrogen. It has been postulated that age has an effect, and I think this likely also, such that younger men may need SP while older men doing NBE do not.
However, the long held misconception (even in the transgender community) that you MUST take an antiandrogen started because the first artificial hormones (primarily premarin and depo provera, two VERY nasty and ineffective drugs) given to transitioning MtF individuals were relatively weak compared to bioidentical hormones available today. The main estrogen in premarin is estrone which is many times weaker than estradiol. If you are taking weak estrogens to cause feminization, it stands to reason it will help greatly to take an antiandrogen. Also, those individuals who have decided to transition are known to want near instantaneous results, and waiting 6 months to a year for their testes to stop producing testosterone is usually unacceptable to them.
I think a similar argument holds for the use of FG versus PM. FG is a WEAK phytoestrogen, while PM has been shown to have similar estrogenic effects as estradiol. check out:
http://scholar.google.com/scholar?hl=en&q=estrogenic+effects+of+pueraria+mirifica&btnG=&as_sdt=1%2C39&as_sdtp=
and
http://journals.lww.com/menopausejournal...id.22.aspx). I would argue that with a stronger phytoestrogen, less or no antiandrogen is required.
In addition, as Isabelle has pointed out, based on her considerable herbal knowledge and research, PM has an antiandrogen in it, which may explain why us older folks have used it without SP to great effect.
Another route to consider, as another poster suggested, is to promote the action of aromatase which converts testosterone to estradiol. There is no back conversion of estradiol to testosterone, and once converted the T is unavailable to be converted into DHT. Forskolin, the active ingredient in coleus forskohlii is known to up-regulate the gene for aromatase. There's lots of info on coleus forskohlii on body building and weight loss forums, as well as
www.scholar.google.com.