Do I mark my child as disabled if she has developmental delay?

[MayaD]

Per IRS A person is permanently and totally disabled if both of the following apply. He or she can't engage in any substantial gainful activity because of a physical or mental condition. A physician determines that the disability has lasted or can be expected to last continuously for at least a year or can lead to death.

[macuser_22]

Disabled makes no difference whatsoever for a child under the age of 13.  It only allow the dependent care deduction if care is necessary because of the disability that normally cuts off at age 13.  It  also allows claiming a child over age 18 as a Qualifying Child dependent.