Frog probability

[bennyboy]

One of the possibilities can be eliminated because there cannot be two females.  2/3 =~ 67%

Yeah I see, you are assigning ordinal values to the two frogs:

MM
MF
FM


But this seems too virtual for me, since it doesn't matter which frog is the first or second.  So I see it as:
MM
MF

The not-calling frog, whichever one it happens to be, is either male or female.  So you can put that guy in the first slot, and your left with only one frog to think about.

I feel I'm wrong, but I can't accept it.