Female Tabby

I have a female tabby. I was woundering if it is rare. She is a twin to her identicle brother. I don't want to sell, I am just curious. please email me anything you know at [email protected]
Thanks Bunches,
Tera

At my mothers work, there used to be this feral cat that we called mama cat, she had many litters, and no one was able to catch her or the kittens, but my mom finally caught one kitten and he was an exact twin with one of his brothers. Don't know if that says anything, but oh well.