It doesn't look like you've been on in a while, however I am looking for Blue Tongue Skinks. Do you still breed? Feel free to email me at kkutlikreptiles (at) gmail.com
If he's over 20g sexing should be pretty easy. If not you may need to wait a while yet. If you take a decent picture of her bum and post it on the forums folks should be able to give you a good idea!