Are you par-chance also filing a state return for some state? If so, what state? It "sounds" like you make have changed the order of tax filers on a joint return, or the order of dependents if you have more than one. Let readers know what state if applicable.
It's also perfectly possible that you have all the right birthdays, but for the wrong people.
Also note that when you change the order of who is listed first on a tax return, that will most definitely cause issues.