How do i identify my RES's gender?

Its really been bugging me and I really have to know! so please help me!
Answers:
Generally you can't tell until they are 4 inches in diameter. Some tips that give you a general idea are that males have long front claws, females have short stubby front claws, males have a concave under belly, females usually have a more flat or convex under belly, males tails are wider and longer than females and females tails are usually short and stubby.
The only way to tell, and to be 100% sure, is when your turtle is 4" in diameter, their cloca (anus) will be either far out on the tail if it's a male and then really close to the body if it's a female. You can't sex them until they're 4 inches because when they're babies and under 4 inches, all of their clocas are close to the body. All of them would be sexed as female when this is not the case.

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As a baby, it is very hard to tell its gender until the turtle is over a year old. But age doesn't really matter. Instead, the size of the turtle does.

how to tell:

Make sure your turtle is at least 4' inches long before determining.

Males

Males have longer front claws.
Long, thicker tail.
The bottom shell is more curved.

Females

Have shorter claws.
Shorter tail.
More flat shell. When fully grown, are significantly larger than males.

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as a general rule males have longer claws, but for a definate gender look at and feel the plastron (bottom of shell) it will be flat if it is a femal, and concave if it is a femal.