Need to know if my turtle is a girl or a boy

Ok, I have dumb questions, but I need to know if my turtle is a girl or a boy.I've had him for more then 2 years, and I still dont know his gender. The lady we bought him from said it was a boy, but I got a turtle book, and it shows the tails of a girl,...

and a tail of a boy and that thats how you determine its gender. But I think it's tail looiks more like a girl's, but my mom thinks its a boy. So how can I figure out if it is a girl or boy? Its tail is short-ish, and stubby, so what does that mean?

um take it to the vet and him/her will tell u!!

uhm look at its face I heard that guys have a reddish color kind of strips and girls have a lighter or none!!

but then again I ainght no vet lol!

pen*s

Didn't say what kind/breed of turtle. The common Box turtle is easily indenified by the color of their eyes, males have a very red iris as where females have a yellow/golden colored iris. 99.9% sure of this as I have successfuly breed them and the hatchings from their eggs lived to be released back to nature after 8 weeks or so protected until large enough to have a better chance of survial, it seems every thing will eat them when babies, just smaller than quarter.