I have mis sexed a sub adult male ball python as a female before. That is why I always probe now to double check popping. But, even that can be misleading. I just purchased a group of adult female balls. One of them is over 2500 grams and probes male. If it is a male it is the biggest one I have ever seen.

I am keeping it an putting it with my spider next year (they won't be out of quarentine in time for this year) just to double check. Hopefully it is a female that has been "popped".