“Parents are more likely to grant privileges to younger children sooner than they did the older kids,” he says. “As a parent, when you say to a 12-year-old, ‘you can stay up until 10’, then maybe the 10-year-old gets to do it too, because [parents] don’t want to fight.” When younger children get permission earlier than an older sibling did, “that can cause the older one to feel things are unfair. That creates conflict”, adds Whitehead.