Conversation so far:
Where was Isaac Asimov born?
Isaac Asimov was born in Petrovichi, Klimovichskiy Uyezd, Russian SFSR.
Are there any other interesting aspects about Isaac Asimov?
Isaac Asimov and 16 other children in Petrovichi developed double pneumonia.
Was Isaac Asimov hopsitalized because of the pneumonia?
Who were Isaac Asimov's parents?
Isaac Asimov's parents were Anna Rachel (née Berman) and Judah Asimov.
Did Isaac Asimov have any siblings?
Isaac Asimov had a younger sister.
Were any of the children who died from pneumonia Isaac Asimov's siblings?
Did Asimov's family ever move from Russia or did he spend his whole childhood in Russia?
Isaac Asimov's family travelled to the United States via Liverpool on the RMS Baltic, arriving on February 3, 1923 when he was three years old.

Question: Why did they move to the United States?
Self-contained rewrite: Why did Asimov's family move to the United States?