query: # items with more child (P40) statements than number of children (P1971)
  # (comparing to the max number of children in case of multiple statements,
  # because some items (e. g. Q91) have several P1971 statements,
  # some with applies to part: children who lived to adulthood)
  SELECT ?item ?itemLabel (MAX(?numChildren) AS ?numChildren) (COUNT(DISTINCT ?child) AS ?countChilden) WHERE {
    ?item wdt:P1971 ?numChildren;
          wdt:P40 ?child.
    SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en". }
  }
  GROUP BY ?item ?itemLabel
  HAVING(?countChilden > ?numChildren)
  ORDER BY DESC(?countChilden - ?numChildren)