You cannot claim your child as a dependent if:
- You are being claimed as a dependent by someone
- Your child is married and filing a joint tax return (unless he/she is filing just to claim a refund of withheld tax and isn’t taking a personal exemption)
- Your child is not a resident of the U.S., Mexico or Canada
- Your child is over 19 and not a full-time student
- Your child is 24 or older on December 31 of the tax year
- Your child provided more than half of his or her own support
- Your child did not live with you for half the year, 183 days or more. Note: the exception to this rule – illness, education, business, vacation or military services, or the child was born or died during the year
- You are separated or divorced, and your child spends more time at your ex-spouse’s home.
see: http://www.TaxEsq.com