In both the original manga and television series, Dr. Boynton (Dr. Tenma in the original Japanese) creates Astro Boy after he is grief-stricken by the death of his son. At first he is pleased with his robotic replacement, but he becomes incredibly angry when he realizes Astro isn’t growing like a real boy. He sells Astro to a circus, where Astro is forced to fight other robots.
Dr. Boynton’s character takes different roles in the manga and TV show after this. He appears multiple other times in the manga, and still has affection for Astro, though he knows he can never be forgiven for what he has done. He helps him out on multiple occasions. In the TV series, however, he is only seen once more after the first episode, and it is suggested that he has either killed himself or been institutionalized.
Dr. Elefun (Professor Ochanomizu in the original) is essentially Astro Boy’s adopted father in both the manga and TV series.
More to come!