Django filter - only select postes depending on filters

Question

**models.py**
class Category(models.Model):
    name = models.CharField(max_length=50)

    def __unicode__(self):
        return self.name

class Gender(models.Model):
    name = models.CharField(max_length=50)

    def __unicode__(self):
        return self.name

class Post(models.Model):
    name = models.CharField(max_length=50)
    categories = models.ManyToManyField(Category)
    genders = models.ManyToManyField(Gender)

    def __unicode__(self):
        return self.name

**view.py:**
def index(request):
    posts = Post.objects.filter(genders=1)
    categories = Category.objects.exclude(outlet=None).filter( ?????? ).order_by('-sort'), 

Now I need to select ONLY the the categories where there are postes in, depending on the given filter "genders=1" How can I do so?

Hope you understand my issue.

Answer 1

.filter( post__gender=1 )