The Black Order is not his actual children
There have been plenty of terrifying alien threats in the MCU, but none can compare to the Black Order. The Order is headed by a wizard-like figure, Ebony Maw, and includes such evil figures as Cull Obsidian, Proxima Midnight, and Corvus Glaive. You are about to die at the hands of the offspring of Thanos,” Ebony Maw says destructively in “Avengers: Infinity War.”
This seems to imply that Ebony Maw and the other members of the Black Order are direct descendants of Thanos. However, there is no simple solution. Thanos selected the Black Order as his particular followers, much like he plucked Gamora and Nebula from their home worlds to train them as members of his guard.
The Mad Titan’s followers are like the Death Eaters to Lord Voldemort since they will do everything for Thanos. However, the Black Order has not been programmed to serve Thanos without question. In the comics, we see Ebony Maw betray the Mad Titan in order to release Thane, and we see Corvus Glaive establish himself as the new Thanos by forming his own version of the Black Order.

