Sexing a gabf please help

[sjboyle]

How can you tell? What signs tell you best?

[SwimminSteve]

I am not an expert, but to me this frog looks female. I'm basing that on the size of the head compared to the body. If you look at other sexing threads, you will see that in general we make subjective judgments on the size of the head. If the head seems "small" compared to the body (like in your photos) it is most likely a female. If the head seems rather large compared to the body it is possibly a male.
I think the only way to be 100% sure is to wait a while longer to see if your frog ever croaks or continues growing past 5 inches.
Very nice, well-fed looking frog BTW! Do you have enough substrate in there (4-5 inches) for her to completely burrow in? It looks like you have an overhead light on, so she would probably appreciate more opportunities for hiding/shade. Just a thought