Melon Head vs Big Head

Today a Bolivian Dr paid attention to Max bald head. He observed the melon-shaped skull and commented that "clear sign of his mother's etnic".
We both raised eyebrows. Etnic.
Then it came a long explanation about the similarities bewteen south american indians and south east asian people. I didnt buy it. Rio's carnival parades and thai ladyboys crossed my mind. "Nahhh"

His following comment was: "and the size is quite big too". There I tried to be quick and reply as fast as I could think: "that must be his father's etnic"
And mama smiled

Sorry Dad