Tortoiseshells have a defective gene and are almost always female. The rare times you get a male they are usually sterile.
My OH found our little one (or she found him) in a field. She was 7 weeks old and had quite a bad facial injury. My then 9 month old cat started hissing when he first saw her, she just stared at him like he was stupid boy and strutted to the food bowl.
They are the best of friends now.