No transplant here - but I am routinely taken for, and told, I am 15 or more years younger than my actual age, and according to Garmin, my "fitness age" is 35. This is due to doing it "the hard way" - and I still do not have my microbiome analysis back from Zoe Nutrition. I believe it will show some positive diversity. There is some basic understanding of health-promoting microbes, and health-detrimental ones, and Zoe is only looking at a total of 30 - as you point out, there are so many, and with individual varied responses and microbiome compositions, it's not as simple as "transplanting that youthful microbiome" ... thank you so much for an amazing, complete discussion of this new research, Sam!