From I read over the internet, most snail can breed without different male/ female. Mean they could either be male/ female, as long as you put two same snail together, they can breed. EXCEPT for apple snails!
Apple snail need to be specificly to have both male and female in order to breed. For me, I have hard time to different shape between the male and female. At first I tough both of my snails are female, then I saw the egg, confirm I got 1 male and 1 female.
Form my observation, i found out male apple snail are smaller and their shell color are ligther and dull. Female are bigger and their shell are brigther in color. In the internet, they do teach us how to different shape, but hardly because they are almost the same except for their "sex" organ!
YES, it mean the male apple snail have the "thing" to put into female apple snail "thing" and I saw it during their mating time.
You can get good info at
www.applesnail.net