Hi, human endocrine researcher here: Wikipedia is garbage for "controversial" medical topics -- it's even worse for many non-controversial biochemical processes (please take a look at the human alcohol metabolism graph... utter garbage!). Citing a few researcher's conclusions (NO! You do NOT do this!) is haphazard, it usually does NOT match the same conclusions one's peers would reach were they to review piece as a whole.

Here's what easily deductively reproduceable with a cursory understanding of the systems involved (and digging through a lot of literature):

> Phytoestrogens bind to estrogen receptors (YES)

> Chemicals -- other than estrogens -- that bind to estrogen receptors are Selective Estrogen Receptor Modulators

> SERMs are NOT the same as estrogens, but they do increase certain estrogenic effects depending on their chemical structure (good: lipid profile, prostate stability; AND bad gynocomastia, electrolyte retention)

> Each SERM has a specific amount of "power" (receptor affinity and corresponding gene expression, i.e how much it increases or decreases the expression of certain genes)

> Soy, and plant products, contain many different phytoestrogens/SERMs, isoflavones are the strongest

Now, onto the goodies:

> The HPTA (Hpyothalmic-Pituitary-Testicular Axis) controls hormone output

> There are estrogen receptors (and others) in the hypothalmus

> Suffice to say, Hypothalmic Hormonal receptors modulate the levels of circulating sex hormones in the body

> When there is an increase of hormones in the body, the excess get bound to hypothalmic receptors, causing the hypothalmus to tell the Pitutary + Testes to produce less hormones OVERALL (FSH, LH, tesosterone, estrogen, etc.)

> Less production of hormones is NOT necessarily bad - Estrogen is the most important hormone in women AND men (take a large amount of any aromatase inhibitor, i.e estrogen "killer," and you will feel a LOT worse than if you were to take an anti-androgen)

> SERMs do decrease circulating hormone levels (by how much is dependent on many variables), due to negative feedback on the HPTA > Once again, this is NOT necessarily bad, because SERMs still bind to estrogen receptors and elicit estrogenic effects on the body

A few for the road:

> Healthy estrogen levels are vital to male libido (as is a proper estrogen:testosterone ratio, too little of either is bad)

> Too little testosterone may also cause too little estrogen, because estrogen is produced in the male body primarily from aromatase (enzyme that converts testosterone to estrogen)

> FSH is involved in sperm production

> LH is involved in testosterone production

This is all the information you need to make an informed opinion on the whole topic. I'm sick of all sides involved. Pseudoscience and agenads, all of you!