There are some situations where you may be asked to provide your child's SSN, but it isn't always necessary. As a general precaution, it may be a good idea to ask the source why you are being asked to provide the number if you are ever unsure of the reasoning, says Experian. Below are a few examples when you may be asked to provide your child's SSN and what you should know:

Starting a new school year: Your local schools may ask for your child's SSN during registration, but they are not allowed to deny your child's enrollment if you choose not to disclose it, according to the U.S. Department of Justice. Additionally, when it comes to protecting the privacy of your child's student records, the federal Family Educational Rights and Privacy Act (FERPA) gives you the right to opt out of sharing contact or other directory information with third parties. Be sure to contact your child's school if you'd like to opt out of sharing this kind of information.
Signing up for after-school activities: When signing your child up for sports or after-school programs, confirm whether providing your child's SSN is truly necessary. Depending on how it will be used, alternate forms of identification may suffice, says Experian. Also, be sure to take note of each program's privacy policies to find out how your child's information will be used and shared.
At the doctor's office: Many healthcare providers ask for a SSN to easily identify and reach you if medical bills go unpaid, according to Consumer Reports. However, giving out your child's SSN is not always a must — instead, the Federal Trade Commission (FTC) suggests offering an alternative form of identification, or only the last four digits of the SSN.