Parent-offspring conflict is like when you and your mom or dad want different things. For example, you might want to stay up late and play games, but your mom or dad wants you to go to bed early so you can wake up early for school.
This happens in animals too, when the needs of a parent and a baby animal conflict. Parents of different species want different things for their offspring. For example, a mother bird wants her babies to grow up fast and strong so they can fly away and start their own families, but her babies want to stay in the nest and be fed by their mother forever.
This conflict happens because each side has a different goal. The parent wants their offspring to survive and pass on their genes to the next generation, while the offspring wants to get as many resources as possible for themselves.
This conflict can lead to some interesting behaviors. For example, baby birds might beg for food even when they're not hungry, just to get their parents to feed them more. And parents might withhold food from their offspring to encourage them to leave the nest.
Despite this conflict, most animals have ways of getting along so that everyone benefits. For example, dogs and their puppies bond and learn to communicate with each other, so they can work together to get what they need.