It’s here: VeriChip’s “RFID for People”

Unashamedly using terms like “RFID for people” and “implantable microchip”, VeriChip’s web site advertises implanted chip solutions for your organization.

VeriChip also have a page that vaguely mentions “RFID infant protection solutions“, whatever that means.

Wikipedia has more about RFID and spychips, as well as a photo of what an implanted spychip looks like.