How big are they these days? I wouldn't be looking for hemipenes yet, they're still very young to be showing them, and they don't do it every time they go. Really the only way to know for sure it's a female is to have it lay eggs.Well, it looks like at least one of these little guys is going away on Sunday at the reptile show as it decided that it would be fun to lock onto the hind foot of one of its cagemate's for 15 minutes & spray me with some unholy mix of musk & feces when I was attempting to separate them.
By the way, I think they're both females as no hemipenes were everted by either when they musked/defecated (the attacked one did so when it got bitten).
I guess we might also see how effective Nile monitor venom is on conspecifics. The attacked one didn't seem to be doing very well during & after the attack, but I hope that it recovers.