Well Pinoko is and and is not 18 at the same time. He body was artificially constructed by Black Jack. She was something like a parasitic twin living in the body of one of his patients. Black Jack removed her and made her a body.
Curious subtext of implied pedophilia in this series. The lap action for going to the zoo? Not your regular happy hug. What's up with that? Can anyone explain the little red headed girl Pinoko's presence in this single male's household?