As you can tell by the title...I've had some issues with incorrectly sexed snakes. To be specific, my Lavender corn snake that I just sold as a female which turned out to be a male!! The buyer confirmed this by placing 'her' with a proven female and getting pictures of the copulation!
I know nothing about sexing snakes, and got that lavender at a reptile expo from a breeder said to be 'very good'. He had the snake marked as female and even told me that he had put it with his male a few times, but got no eggs (well now we know why not). A friend of mine even tried to pop 'her' and saw nothing, so they proclaimed it female as the breeder said. I had no reason to doubt, so I sold the snake as a female. I hate having a 'black mark' on my selling record, as it were.
What this tells us is to ALWAYS have a professional breeder or vet, someone proven and experienced, check our snakes sexes! To this end, I am going to be searching the Seattle area for just such a person who might double check my 7 snakes (two of which I wish to sell) for little money or free, since I still don't have a job/income. I will be having them all checked, even though my albino male was bought from a trusted breeder who saw him produce plugs, and my female pastel was also from a trusted breeder. I don't want to get burned again...