@dragnucs If you're going to present user info (in a API or exported to files) consider using vCard format, which includes BDAY https://tools.ietf.org/html/rfc6350#section-6.2.5 ; if you're displaying user info on a Web page then mark it up with h-card #microformats http://microformats.org/wiki/h-card which are a web-specific API for vCards