Everybody's got a holiday shtick and August 12 celebrates National Middle Child Day, reported WFSB. Middle kids are the center of attention on this day devoted to not-the-eldest and not-the-youngest sibling. Or siblings: families with more than three kids may have two, three or 12 middle children! So what do we know about middle kids? One study says they're the most jealous, shy and quiet.Middle kids are center of attention on National Middle Child Day - Grand Rapids News | Examiner.com