Very young children (7)
I believe the answer is:
infants
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">very young children</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for infants that I've seen before include "Small babies" , "Little ones" , "Young babies" , "Very young children" , "Very small humans" .)