Sihamoni was born in 1953.
His given name, Sihamoni, comprises two morphemes from his parents' given names, Sihanouk and Monineath.
At the time of his birth and that of his younger brother, his mother Monique Izzi, a Khmer citizen of Corsican and Khmer ancestry, had been one of King Norodom Sihanouk's consorts after being a constant companion since the day they met in 1951, when she won first prize in a national beauty contest.
She was granted the title of Neak Moneang and the name of Monineath at the time of her marriage to King Norodom Sihanouk in 1952.
Furthermore, Queen Monineath is a step-granddaughter of the late Prince Norodom Duongchak of Cambodia, and the daughter of Pomme Peang and of her second husband, Jean-François Izzi, a Corsican banker.
The Royal Ark website entry about the genealogy of the Cambodian royal family states that Sihanouk and Monineath were married twice, once on 12 April 1952, when she was 15, and again ("more formally", according to the website) on 5 March 1955.
She is described as Sihanouk's seventh wife.

Sihamoni has 14 half-brothers and half-sisters by his father; his only full sibling, a younger brother, Samdech Norodom Narindrapong, was born in 1954 and died in 2003.
Sihamoni was born in 1953. His given name, Sihamoni, comprises two morphemes from his parents' given names, Sihanouk and Monineath. At the time of his birth and that of his younger brother, his mother Monique Izzi, a Khmer citizen of Corsican and Khmer ancestry, had been one of King Norodom Sihanouk's consorts after being a constant companion since the day they met in 1951, when she won first prize in a national beauty contest. She was granted the title of Neak Moneang and the name of Monineath at the time of her marriage to King Norodom Sihanouk in 1952. Furthermore, Queen Monineath is a step-granddaughter of the late Prince Norodom Duongchak of Cambodia, and the daughter of Pomme Peang and of her second husband, Jean-François Izzi, a Corsican banker. The Royal Ark website entry about the genealogy of the Cambodian royal family states that Sihanouk and Monineath were married twice, once on 12 April 1952, when she was 15, and again ("more formally", according to the website) on 5 March 1955. She is described as Sihanouk's seventh wife.
Sihamoni has 14 half-brothers and half-sisters by his father; his only full sibling, a younger brother, Samdech Norodom Narindrapong, was born in 1954 and died in 2003.
Norodom Sihamoni