Reptile & Amphibian Forums

I am very curious of something that I had just heard today. Someone told me that monitors are all born without sex and that the dominant ones become males and the others become females. I have also heard that someone had a Male water monitor and it later laid eggs, but they are 100% positive it was a male prior. This is a retail location giving out this information and i am wondering if they are enlightening me and the rest of their customers, or if they are filling our heads with lies. They did say that this was only a theory, but I thought that theory had been disproven. The water monitor belonged to them and they claim it as fact. Thanks

sorry