You will not be able to sex your frill until after a year. When they are first hatched you can look at the base of the tail and make 90% guess because you can se the hemis. But then fat storage covers them up; and popping is scary with these guys. They are not like Beardeds. I had really nice baby that I thought was female, but now that it is growing I think its a male. go figure...
Full grown adults are easy. BUT.. not if they are recent imports that are under weight and dehydrated. I get emails all the time from people that buy imports and the sex ratio is wrong, really wrong.

This animal in the post I thought was a female since its frill was really short; now I thinks its male.
Just be patient and take good care of the he-she.
cheers,
miz

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Mizzy: frilldragon.com