Currently in Palworld, it is confirmed that up to four (4) Passive Skills can be inherited by the child Pal from the passive skills pool of the (2) two parent Pals.
You Can Also Inherit All Passives
It has been confirmed that it is possible to inherit all four (4) Passive Skills from a parent. Therefore, there is a total of 0/8 chance to inherit from two (2) parent Pals with 4 Passive Skills each.
Random Passives Occupy Empty Slots
If there are three (3) or less passive skills inherited from a parent, the remaining empty slots have a probability of being assigned a random Passive Skill.