Herbert Hugo Stein was born in Bremen on June 27, 1925, the son of Willy Stein, a grain merchant, and his wife Charlotte, née Blank. His younger brother Kurt Gustav was born on August 4, 1930. The brothers enjoyed a sheltered youth; their religious upbringing was Jewish Reformed Conservative, but not very strict. In 1934 his father's company was expropriated, and in 1936/37 the family moved to Berlin and lived at Gossowstraße 1, a house that belonged to his mother, above an inn with a bowling alley.

Charlotte Blank was born in Berlin on September 9, 1898, the daughter of the factory owner Gerhard Blank and his wife Rosa, née Blank.

Max Spittel was born in Aachen on November 21, 1876, the son of the merchant Nathan Spittel and his wife Bertha.