Hollywood isn't known for being particularly concerned with realism. This is manifested in a variety of ways, especially when it comes to casting. From onscreen relationships with creepy age gaps to 30-somethings portraying high school students, casting choices can make things uncomfortable fast.
Some of these casting decisions can obviously be excused to some degree. After all, real-life couples often have pronounced age gaps. However, when it comes to movie parents and their offspring, there is no good reason to cast actors that are practically the same age. You might be surprised to learn how often onscreen mothers and fathers are just a few years older than their fictional children. In some instances, the actor playing the child may even be older than their parents.
Heath Ledger: 26
Kate Mara: 22
Age Difference: 4 yearssee more on Heath Ledger
Angelina Jolie: 29
Colin Farrell: 28
Age Difference: 1 yearsee more on Angelina Jolie
Drew Barrymore: 26
Adam Garcia: 28
Age Difference: 2 yearssee more on Drew Barrymore