I hate to be the one that sounds like an idiot, but I've never heard of such a thing. These experts do know that it can be hard to sex a box turtle sometimes if it hasn't reached sexual maturity, right? I mean, a turtle can be several years old and its eyes not turn color or its plastron not get concaved. Again, I hate to say I've never heard of this and everyone on here refute me, but it sounds more like a case of not being able to tell the sex yet because of age or other circumstances.

I also saw you asked about calcium sources. I don't use that powder stuff. I recommend providing calcium through natural sources like collard, turnip and mustard greens, snails, dandelions.

Tess' website has a good page on Calcium sources. http://www.boxturtlesite.info/min.html