The protagonist and another character are medically tortured. The protagonist'torture is somewhat glossed over, the other character is tortured gruesomely, including mutilation and bodily modification as well as medical experimentstion
Depends on interpretation. Two characters technically share a mother (one by birth, the other by a genetic material donation to their tapeworm-self), but they do not view each other as family.
One of the Chimeras prefers a male form, but is currently implanted in a female body. Both characters and the narration refer to this character as "she", despite their protests.
Mentions of Antiparasitics used to remove D. Symbogenesis (a semi-sapient parasite) from a human body. Some discussions do resemble modern conversations regarding abortion.