Males will usually be about an inch smaller and will call, maybe when they are about a yr old you can tell.

Breeding is quite the undertaking, you'll need at least one female and several males. Then you need a rainchamber and cooling periods (it's a big production.)

http://monkeyfrogs.com/agalychniscallidryas/breeding.shtml

You should always try to get CB animals, check with breeders for multiple animals.