Not a whole lot unless you consider the human species to be generally disturbing.
The most disturbing I've learned, and I already had a vague idea of it beforehand, was:
Uncomfortable genital discussion
Visibly intersex babies usually being put through genital mutilation surgery at birth, normally causing dysphoria as they get older, as well as causing distress if they learn what happened to them as infants.
There are cases where parents are decent human beings, and allow their babies to stay as they are so the kid can figure stuff out when they're old enough, but it's apparently a rarity since doctors also push for the surgery.
