I should hasten to add that about all that I personally know about stem cells is the use of their plasticity and that for many the degree of plasticity is reflected by the stage of development. (This is why the very earliest embryos, the ones small enough -- a few cells only in size -- to be implanted after laboratory fertilization -- but which aren't used for that intended purpose so would otherwise just be trashed -- have been the preferred cells for research. I know also a few basics, a few promising uses for truly terrible diseases, and that the existing new report on stem cell research was declared unacceptable by the administration just last week and the team responsible changed last week to reflect only one religious take and to not reflect scientific takes, meaning that the report will become virtually meaningless and will be delayed for release until sometime next year. That's close to the sum of what I know myself. I don't know if the tissue harvesting the writer asked me about a month or so before would even make sense; that knowledge would take information I haven't check into. I simply figured the person had good reason to ask so respectfully sought out some info on who was using ferrets in stem cell research so that the person could work outward from that lead. I wish I'd gotten an update and still hope to. It is also important to recall that in pathology reports it has been noted that there are differences in the rates of tumor types between BFFs and domestic ferrets (said because of my mention of http://www.nsf.gov/od/lpa/news/03/pr0370.htm ). For instance, beyond levels which seem to pathology experts to trace to differences in rates of sterilization, domestic ferrets are more prone to adrenal growths and BFFs to primary mammary malignancies. Hope that helps and hope that some of the those links are useful to you! [A later] P.S. BTW, I am not in the least disagreeing with what Bob said. His points were not only valid but excellent. I just figured that people might like to know about a study which can impact both impregnation and tumor work in ferrets, and about ways in which ferrets are involved in research on stem cells for human health use ( with human use under study including but not limited to for cystic fibrosis -- a study which closely involves ferrets), retinal degeneration, glaucoma, parkinsons, diabetes, etc. I lacked time so put in some things which are very accessible to the vast majority of FML members so that people have what they need to create a firm enough starting point for further delving of their own (for those of us who never stop being curious). I found myself wondering if the person who asked him was the same one who asked me about uses and I remain curious about a follow-up on that particular score. BTW, in one of those sites (I think the innovations one) is a short and very clear write-up on a neat study in which normal mice were grown from mouse brain tumor cells, a study which gives an interesting perspective on the multi-factor initiation of successful malignant cell growth. It will be of interest to anyone who wants to know more on malignancies in general. [Posted in FML issue 4494]