At the moment most foster kids in England have to leave home by their eighteenth birthday, but a group of charities want change to that law.
They say many young people aren't ready to leave home until they're much older.
If the change were to happen it would mean foster kids can stay with their families until they're 21.
At the moment the average age for leaving home in England is 24, according to the charity The Fostering Network.
Most foster families look after kids until they are 17. They can stay longer but the money foster parents get from the government to care for the children does not cover them after they turn 18.
A trial study to change the age to 21 took place in 11 areas across England. The study found that young people who stayed with foster carers were twice as likely to be in higher education at the age of 19 than those who did not.