controller.js

var query = { $and : [ 
                { idFace : { $in : [req.body.idFace] } }
              , { "users.gender" : 'male' }
            ]}
  ;

Model.find( query )
  .populate({
      path : 'users.user'
    , match : { gender : 'male' }
  })
      .exec( function( err, data ){
          if (err){ console.log( 'Erro: ' + err ); return res.json(err); }
          console.log( 'Sucesso: ', data );
          res.json( data );
      });

model.js

(function(){
	'use_strict'

	var mongoose = require('mongoose');

	var Schema = mongoose.Schema;
	
	var UserSchema = new Schema({
		_id : false
	  , user : { type : Schema.Types.ObjectId, ref: 'User' }
	  , gender : { type : String, default : '' }	
	});

	var EventoSchema = new Schema({
	    idFace : { type : String, default : '' }
	  , name : { type : String, default : '' }
	  , matchs : [{ type : Schema.Types.Mixed }]
	  , likes : [{ type : Schema.Types.Mixed }]
	  , users : [UserSchema]
	});

	module.exports = mongoose.model( 'Evento', EventoSchema );

})();