"I have a recipe that calls for she-crab. Is it possible to tell the difference between a male and female crab? "
It is all in the way they wear their aprons! Seriously, when you turn a crab over, you’ll see what is called the apron in the center of the underside. She-crabs sport a wide triangle shaped apron, while male crabs’ (aka Jimmies) aprons are narrow, fairly straight up and down with a small triangle at one end, almost like a T.
Spring she-crabs get flavor from their roe (which also lend an orange color to soups and sauces). It is a matter of debate whether older or non-egg bearing she-crabs have a different flavor and texture from their male counterparts.
Here's a recipe from Coastal Living for she-crab soup: She-crab Soup