Well, good luck! if you get good enough at it you can sex them pretty accurately just by looking and no popping. In fact I sexed my red striped babies first by looking and then afterwards popping to be sure and it turned out I was right just by visual sexing! But there's always that one "male" that's actually just a female with a thick tail... and vice versa! what I like about popping my babies is it requires very, very little pressure to do, and I absolutely hate not being sure about sexes!!! (perfectionist...) I own probes, but I would never probe a thamnophis... as adults there is simply no need to as they are easily sexied visually, and as babies they are just far too tiny and tender!