Is Young Black Jack hentai?
No
Rated PG-13 (Teens 13 or older) on MyAnimeList and not tagged as Hentai.

TV · 2015 · 12 episodes · PG-13 - Teens 13 or older
Drama, Historical, Medical, Seinen
In the 1960s, a gifted young medical student tries to make a name for himself. Kuroo Hazama is a reserved young man with unusual black-and-white hair, a body covered with scars, and a dark past. Despite only being a medical student, his surgical brilliance starts to attract attention after he completes a seemingly impossible operation. Together with the spirited and honest intern Maiko Okamoto and Yabu, a close friend with a troubled life, Hazama devotes himself to the world of medicine. However, his path to becoming a respectable surgeon is a difficult one as student riots, war, and corruption are consuming Japan. Hazama quickly finds himself caught up in a series of nefarious circumstances that challenge his integrity as a person and his path towards becoming a surgeon. Young Black Jack chronicles the story of a man capable of performing unthinkable feats of medicine, and the journey that leads him to become the legend known as Black Jack. [Written by MAL Rewrite]
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