Donatien Alphonse Francois de Sade was born on 2 June 1740, in the Hotel de Conde, Paris, to Jean Baptiste Francois Joseph, Count de Sade and Marie Eleonore de Maille de Carman, cousin and Lady-in-waiting to the Princess of Conde. He was his parents' only surviving child. He was educated by an uncle, the Abbe de Sade. In Sade's youth, his father abandoned the family; his mother joined a convent. He was raised with servants who indulged "his every whim," which led to his becoming "known as a rebellious and spoiled child with an ever-growing temper."  Later in his childhood, Sade was sent to the Lycee Louis-le-Grand in Paris, a Jesuit college, for four years. While at the school, he was tutored by Abbe Jacques-Francois Amblet, a priest. Later in life, at one of Sade's trials the Abbe testified, saying that Sade had a "passionate temperament which made him eager in the pursuit of pleasure" but had a "good heart." At the Lycee Louis-le-Grand, he was subjected to "severe corporal punishment," including "flagellation," and he "spent the rest of his adult life obsessed with the violent act." At age 14, Sade began attending an elite military academy.  After 20 months of training, on 14 December 1755, at age 15, Sade was commissioned as a sub-lieutenant, becoming a soldier. After 13 months as a sub-lieutenant, he was commissioned to the rank of cornet in the Brigade de S. Andre of the Comte de Provence's Carbine Regiment. He eventually became Colonel of a Dragoon regiment and fought in the Seven Years' War. In 1763, on returning from war, he courted a rich magistrate's daughter, but her father rejected his suitorship and instead arranged a marriage with his elder daughter, Renee-Pelagie de Montreuil; that marriage produced two sons and a daughter. In 1766, he had a private theatre built in his castle, the Chateau de Lacoste, in Provence. In January 1767, his father died.

Answer this question "Did he have siblings?" by extracting the answer from the text above.
He was his parents' only surviving child.