Is my cat male or female

Is my cat male or female

In October, my brother found a skinny little cat wandering around in a field near our house. We took in the cute little thing. It's a beautiful cat and did not seem to be just another stray. It's possible that this cat belonged to someone at one time, therefore could have been spayed or neutered, but it was so skinny and frail, he obviously no longer had a home. Well anyway, what I want to know is how to tell if its male or female? Could some please let me know in any way how to tell, or what to look for? Keep in mind, it could have been fixed. Thanks