If you can post a pic of the underside of him or her. You can get a pretty good idea most of the time by looking at the epigastric furrow (vent between the top book lungs). If you can get a picture of her (like crawling on the side of the tank if you don't want to pick her up for a underneath shot) I can probably give you a good idea of gender, then when he/she molts you can see if I was right