@ Donna: if you get two of the larger shrimp from the store there is a good chance that you will get two females. Even if you do get a male and a female, ghost shrimp are dificult to raise to adult-hood. Baby shrimp are a great food source for all other fish. That is if they do not get sucked up into the filter system first. Baby shrimp are also very difficult to feed. Unless you buy them special fry-formula fish food, they will simply starve and be eaten by either your fish or the other larger shrimp. So, they are not like pond snails that will overwhelm your tank. You should be fine.
They can be fun to watch though. The females carry the fertilized eggs under their tails. Once they hatch the shrimplettes are on their own, and very small.