Can my child refuse a doping test, or can I refuse on their behalf?

Refusing is itself a violation. Under Article 2.3 of the SAIDS Anti-Doping Rules, evading sample collection, or refusing or failing to submit to it without compelling justification after being notified, is an anti-doping rule violation, whatever a later test might have shown. This applies to minors too.

Bans under Article 10.3.1:

• Usually 4 years.
• 2 years if the athlete shows the failure to submit was not intentional.
• For a Protected Person (under 16, or under 18 and not an elite athlete), anywhere from a reprimand with no ban up to 2 years, depending on their degree of fault.

Having a parent or representative present is recommended for a minor but not compulsory, and a test is not invalidated because one could not be found. The athlete may ask to delay reporting to the doping control station for a valid reason.