How old are the red eared slider turtles when you know the gender?

The gender of a turtle does not affect the age of the turtle. You can tell the age of your turtle by looking at the layers on the turtles scute. Scutes are what makes a turtles shell look quilted. Each scute sheds about once a year, revealing a new scute and leaving a layer on the new scute. By seeing how many layers are on a scute you can tell how many years old your turtle is. Example. 2 layers = 2 years, 10 layers = 10 years. A turtle with no layers will be less than a year old.