Newly born males may confuse you until their nostrils harden and starts discolouring. And there you have the single factor needed to sex your badgie: Males have darkened, blue to grey purple nostrils. There is a word for those nostril growths, you know? Anyway, females remain sort of pinkish cream all their life, and males become dark. That's it, you don't even have to open the cage. I must still see how this translates for the albino yellow ones...