Erblichkeit; Heredity; Grammar gene; FOXP2; Language and genetics ; Aggression research ; Affect (language acquisition) ; Spracherwerb und neurologische Entwicklung; Language acquisition and neurological development; Sprache und Denken (Ontogenese) ; Language and thought (ontogenesis) ; Cognitive development; Language acquisition and cognitive development ; Autism ; Morbus Down; Mongolismus; Trisomie 21; Down's syndrome