query: # people who were born on the same day their mother died
  SELECT ?child ?childLabel ?motherLabel ?date ?causeLabel WHERE {
    {
      SELECT ?child ?mother ?date ?cause WHERE {
        ?child wdt:P31 wd:Q5;
               p:P569/psv:P569 [ wikibase:timeValue ?date; wikibase:timePrecision 11 ].
        ?mother wdt:P31 wd:Q5;
                p:P570/psv:P570 [ wikibase:timeValue ?date; wikibase:timePrecision 11 ].
        ?child wdt:P25 ?mother.
        OPTIONAL { ?mother wdt:P509 ?cause. }
      }
    }
    SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en". }
  }
  ORDER BY ?date