Its no accident that babies start putting things in their mouths as soon as they gain enough dexterity to pick things up.  "They're doing that because they're sampling the environment and building their immunity. That's an evolutionary trait," Sawyer says.  
Sikuti ndi ngozi kuti ana amayamba kuyika chilichonse mkamwa mwawo pamene ayamba kutha kugwira zinthu. "Amachita izi chifukwa amakhala akuzindikira malo omwe awazungulira komanso kumanga chitetezo chawo cha mnthupi. Uku ndiye kusintha," a Sawyer anatelo.