Times article (from 5 years ago) describing an emerging awareness of gut-bacteria types much like blood types:
<a href="http:&#x2F;&#x2F;www.nytimes.com&#x2F;2011&#x2F;04&#x2F;21&#x2F;science&#x2F;21gut.html?_r=0" rel="nofollow">http:&#x2F;&#x2F;www.nytimes.com&#x2F;2011&#x2F;04&#x2F;21&#x2F;science&#x2F;21gut.html?_r=0</a>