Wow, really? Are they the only ones that aren't hermaphroditic? That's the first I've heard of it but that's really cool to know!
Nope - Japanese Trapdoor snails are either male or female AND are live bearing snails - the female will give birth to one live snail for about 2 weeks straight. You can easily tell the gender because one has two long antenna and the other has one short and one long. I forgoet which is which but I thin the male has the long and short antenea. They are not normally sold in petsmart/petco but some online sellers have them. I took mine from a lake this summer.
On the right is the apple snail, big moss ball on the left - adult trapdoor snail.
NOTE: Fish on the right is not dead. Some people asked in the past if she was. and the green one turned into a male.