So there are 39 trillion bacterial cells in a human body, and ~30 trillion &#x27;human&#x27; cells in our body. EXCEPT that 25 of the 30 trillion human cells in our body don&#x27;t even have any human DNA in them (red blood cells lack a nucleus, cannot divide, and do not contain human genetic information).<p>So depending on how you draw the line there are 39 trillion non-human nuclei in a human body, and only 5 trillion human nuclei. That brings our non-human:human genetic ratio right back to 10:1.  Though that too is misleading given the amount of DNA in each of those nuclei. (human cells have significantly more DNA in their genome than bacterial cells)<p>These headlines are ridiculous.