How to count multiple times in a single query in MongoDB?

So I have this code:

db.collection.find( { sex: 'Male' } ).count()
 

And what I want to do is count both sex: 'Female' instead of

db.collection.find( { sex: 'Male' } ).count()
 db.collection.find( { sex: 'Female' } ).count()
 

Is there a way to do this in a single query? Because I am generating a pie chart based on its length. Any help will be greatly appreciated.

1> Xiaozhi..:

db.collection.aggregate([
     {"$group" : {_id:"$sex", count:{$sum:1}}}
 ])