[Tiffani Toy]

Always wondered this myself as well. As for the natural thing, natural isnt always safe, you can still take natural phytoestrogens and send yourself into kidney and liver failure by overdosing your limits and making your body chemistry so far gone that it can kill you. I guess it plays into the saying, too much of a safe thing is dangerous still.
Only difference i can think of without researching online a bit just an off the head assumption is the difference of synthetic and natural. I assume natural you are more in control perhaps, opposed to medicinal hormones you are given an amount to take and that is that. I'm sure im very wrong but its just my guess