Autistic people are the only ones on the planet who are incapable of experiencing fear. If you meet someone who has never felt any kind of fear in his entire life, that person is most assuredly autistic. The amygdala (fear center) of every autistic brain is inactive.
Alex Honnold, the expert free solo climber in the attached photo, has never felt fear. His amygdala has been documented to be inactive. Alex’s father had Asperger syndrome (high functioning autism). It appears that Alex does also.
Alex occasionally intellectualizes about fear, saying that he thought about a particular challenge and figured it could be pretty scary. But thinking and figuring out what fear could mean is not the same as actually feeling fear.