The terminology around here is a real tangle of vines--but after all, if you think about it, if bio-identical to human hormones weren't synthesized in the lab that would mean they were taking them all out of some poor woman and selling them to someone else.
It's because of the confusion that we call them bio-identical--and frankly, I just encountered another term that's even better--Human Identical. The laboratories start with yams and soy (for the most part) and change them into the exact same molecules that our bodies produce. So they are made (synthesized) but what you take is chemically just like what you used to make.
In some senses, conjugated equine estrogen/Premarin is more "natural" in that less is done in the laboratory to it but almost none of the 26 steroid metabolites in Premarin occur naturally in the female human body. They occur in horses. So it's bio-identical--if you're a horse!!!
So, for some of us, the horse molecules fit our cells just fine and Premarin works well (or even better for some). But for others, the fact that the fit is close but not identical is bad.
So, all we really care about is whether the chemicals in the cream/pill/patch are human identical. How the chemicals became human identical we'll have to leave to the wizardry of science.