I attended a lecture last year that dealt with Guan Yin and the fact that originally Guan Yin was male. The theory being presented was that Guan Yin was transformed into the goddess of mercy and depicted with a child because of the encounter with the Nestorian Christians who evangelized China with their devotion to Mary and the Child Jesus.
How fascinating. I've often wondered about the reason for the changing gender of the Kuan Yin figure. I've always seen the feminine Kuan Yin as a nearly identical archetype of Mary, but you point out a plausible historical reason, rather than mere coincidence.