If you're comfortable with a little development, you could achieve this by:
Make both your views (I'll call them 'Boy' and 'Girl') hidden. I did this recently in CAML, but you probably could use the object model.
Create an application page to redirect users from this new page to the appropriate view. You can implement your own business logic here, however you want. Note that when redirecting, you'll need to make sure your GUIDs are upper case. Also, throw an exception if they don't have rights to either view.
Add a link to your redirection page to your navigation, so that users can be redirected.
Now, this solution isn't perfect - it prevents users from seeing the existence of the view(s) to which they lack rights, but doesn't stop the view from working if they type in the correct URL.
I guess a final step would be to add a control or some code to the pages for the Boy and Girl views to check the same business logic as the redirection, and if the user lacks rights to see that page, throws an exception. However, this does not secure the individual items against viewing - but I doubt you can achieve that without simply applying Item level permissions against items on your list.