Can a person under 18 have a credit report?

Yes, adding a child as an authorized user on a credit card can cause the lender to report the child's information to a credit bureau resulting in a credit report being created.

A credit report for a minor can also be created through more nefarious means such as when the minor is the victim of identity theft or if they apply for credit and misrepresent their age in order to not appear to be a minor.

If you are the parent or legal guardian of a minor (the credit bureaus try to avoid disclosing the credit report of a minor to anyone else), you can request a copy of your child's credit report. Annualcreditreport.com suggests that you do this by supplying each credit bureau with your child's complete name, address, date of birth and a copy of the their birth certificate and social security card. Also provide a copy of your driver's license or other government-issued proof of your identity, which includes your current address, and a current utility bill containing your current address.

The mailing addresses for the credit bureaus are:

Equifax
P.O. Box 740256
Atlanta, Georgia 30374

Experian
P.O. Box 9554
Allen, Texas 75013

TransUnion
P.O. Box 6790
Fullerton, CA 92834