You are not entitled to claim a child as a dependent exemption on your return until they have been born. For example, if a child is born in February of 2014, you may be able to claim them as your dependent on your 2014 income tax return, assuming all other relevant criteria has been satisfied, but you would not be able to claim that same child as your dependent on your 2013 income tax return since the birth took place in 2014.