>But when I executed this code, return male , why?
You don't evaluate the input string but only the "bool male" that is allways true!
Try this:
static void Main(string[] args)
{
string gender;
Console.WriteLine("Please enter your gender");
gender = Console.ReadLine();
if ( genger == "female" )
{
Console.WriteLine("Your gender is female");
}
else
{
Console.WriteLine("Your gender is male");
}
Console.ReadLine();
}