This is the description from the seller. "During his St. Louis Cardinals years Mark McGwire worked with the Alliance of the American Dental Association with a grant from Oral Health America and the Foundation for Dental Health Education to produce a collector card promoting oral health. McGwire's father was a dentist and it apparently was through that connection that this card project was initiated.
I am a dentist myself. I originally purchased a package of these cards from the American Dental Association for distribution to our young baseball conscious patients.