The sex of a turtle is not determined by its pattern. It is usually determined by the shape of the underside of the shell. A male turtle usually has a somewhat concave bottom shell, while a female turtle's bottom shell is more flat.
Another method to determine the sex of a turtle is by the shape of the tail. The tail of a male is usually wider and "stubbier" than that of a female turtle. See link below for further information. It includes pictures demonstrating the differences between male and female turtles/tortoises.