Chose Membergroup On The Register Page
 

How do you put a drop downbox on the register page, to give new members the option to pick a usergroup?

I've got a normal Members group where all the new members go into, but i wanna give them a option to choose either:

Members,
Female Members,

Please can you give me a step by step guide to do it.

I havent made the Female member group yet, just incase it needs some different settings...

Thanks