2. Most missing children are abducted by a non-custodial parent or family member. Over 800,000 children under the age of 18 are reported missing each year. Of that number, one fourth (nearly 200,000 children), are abducted by a non-custodial parent or grandparent. Abduction by non-custodial, foreign national parents makes up about half of that number. And the real glitch is that international laws make it difficult to prosecute this type of abduction.