Sometimes farang experts can be doped too.
I went back to look at the fairies' and apsaras' picures again, and saw that (according to the imagination of some artists)some fairies did have navels... Well, well, well.
Of course the navel is one of the cutest part of the female human body. And if the (human) artists want to depict fairies as cute and pretty ladies, they probably would imagine fairies to have navels like their human counterparts.
But just think a bit... back to Biology 101. The navel is what was left of the channel where we humans got our nutrients from our moms back when we were still in moms' wombs. If the apsaras are Oppatika "beings which are just born by themselves" from the sea, not from any mother, then they should not have any navel at all???
I guess we have discover one way to prove if a given lady is human or non-human : look for her navel. Anyone want me to conduct the test on her?

But first I have to be sure I myself am human - Aha... I have my navel, ladies and gentlemen. I looked and found it right where it should be. Therefore, I am not an alien, am I?