For those of you who don’t know, the hygiene hypothesis is the claim that autoimmune diseases and allergies and other immune problems are caused b/c people in more clean environments lack exposure to the “real world.” This study shows that lab mice, the ones in those sterile environments, have messed up immune systems compared to mice from the real world — who face real pathogens and real dirt, among other things.

So… think twice before you triple HEPA-filter your kid’s breathing room.

And if your spouse/sibling/parent tells you that your room is dirty, explain to them how it contributes to your healthy immune system