How do you determine the sex of a snail? We keep calling ours a boy, but we don't know how to tell for sure.

thanks again.

From your previous post, I'm guessing you have an apple snail. They are either male or female. See applesnail.net for sexing information. If you can tell from the photos that you don't have an apple snail, then most other snails are hermaphrodites which means they contain both male and female organs. They can produce babies without mating or mate and both of them lay eggs. So, they are both sexes at the same time.

are there acually enny snails that are single sexed :)

Yes, apple snails (including many species, see applesnail.net) and trapdoor snails are two examples of snails that are either male or female.