Go to raws, find "entity_default".
Under [ENTITY:MOUNTAIN], scroll down to ethics section.
[ETHIC:KILL_ENTITY_MEMBER:PUNISH_CAPITAL]
[ETHIC:KILL_NEUTRAL:ONLY_IF_SANCTIONED]
[ETHIC:KILL_ENEMY:ACCEPTABLE]
[ETHIC:KILL_ANIMAL:ACCEPTABLE]
[ETHIC:KILL_PLANT:ACCEPTABLE]
[ETHIC:TORTURE_AS_EXAMPLE:UNTHINKABLE]
[ETHIC:TORTURE_FOR_INFORMATION:UNTHINKABLE]
[ETHIC:TORTURE_FOR_FUN:UNTHINKABLE]
[ETHIC:TORTURE_ANIMALS:UNTHINKABLE]
[ETHIC:TREASON:PUNISH_CAPITAL]
[ETHIC:OATH_BREAKING:PUNISH_CAPITAL]
[ETHIC:LYING:PERSONAL_MATTER]
[ETHIC:VANDALISM:PUNISH_SERIOUS]
[ETHIC:TRESPASSING:PUNISH_SERIOUS]
[ETHIC:THEFT:PUNISH_SERIOUS]
[ETHIC:ASSAULT:PUNISH_SERIOUS]
[ETHIC:SLAVERY:PUNISH_CAPITAL]
[ETHIC:EAT_SAPIENT_OTHER:UNTHINKABLE]
[ETHIC:EAT_SAPIENT_KILL:UNTHINKABLE]
[ETHIC:MAKE_TROPHY_SAME_RACE:APPALLING]
[ETHIC:MAKE_TROPHY_SAPIENT:SHUN]
[ETHIC:MAKE_TROPHY_ANIMAL:ACCEPTABLE]
Relevant part:
[ETHIC:EAT_SAPIENT_OTHER:UNTHINKABLE]
[ETHIC:EAT_SAPIENT_KILL:UNTHINKABLE]
[ETHIC:MAKE_TROPHY_SAME_RACE:APPALLING]
[ETHIC:MAKE_TROPHY_SAPIENT:SHUN]
[ETHIC:MAKE_TROPHY_ANIMAL:ACCEPTABLE]
This tells the game that dwarves are forbidden from using sapient body parts in cooking or crafting.
If you want to use sapient parts just change the line to "ACCEPTABLE".
Eg. [ETHIC:MAKE_TROPHY_SAPIENT:ACCEPTABLE]
For the curious:
[ETHIC:EAT_SAPIENT_OTHER:UNTHINKABLE]
[ETHIC:EAT_SAPIENT_KILL:ACCEPTABLE]
[ETHIC:MAKE_TROPHY_SAME_RACE:UNTHINKABLE]
[ETHIC:MAKE_TROPHY_SAPIENT:UNTHINKABLE]
[ETHIC:MAKE_TROPHY_ANIMAL:UNTHINKABLE]
[ETHIC:EAT_SAPIENT_OTHER:UNTHINKABLE]
[ETHIC:EAT_SAPIENT_KILL:UNTHINKABLE]
[ETHIC:MAKE_TROPHY_SAME_RACE:ACCEPTABLE]
[ETHIC:MAKE_TROPHY_SAPIENT:ACCEPTABLE]
[ETHIC:MAKE_TROPHY_ANIMAL:ACCEPTABLE]
[ETHIC:EAT_SAPIENT_OTHER:PERSONAL_MATTER]
[ETHIC:EAT_SAPIENT_KILL:PERSONAL_MATTER]
[ETHIC:MAKE_TROPHY_SAME_RACE:ACCEPTABLE]
[ETHIC:MAKE_TROPHY_SAPIENT:ACCEPTABLE]
[ETHIC:MAKE_TROPHY_ANIMAL:ACCEPTABLE]