Paternity test after a decade?

This might be a change but when I was in high school I was in a very sexual relationship. She broke up with me and about nine months later gave birth to a kid supposedly with the guy she was cheating on me with. A number of years later and my daughter was born. Who looks almost exactly like my ex-girlfriend's first born. This is where it gets difficult. Both my ex girlfriend and the mother of my children are half Hispanic while I am white. The guy my high school girlfriend cheated on me with was also hispanic.I can't shake the feeling that my ex had a kid who shares my DNA. Her daughter is tall and lanky, and considering me as their father, could easily be mistaken for my daughter's sister. My daughter has dark blonde hair that matches my sons while my ex's daughter has light brown hair that only matches the youngest of four kids. Seriously, if it was any lighter it would be considered blonde despite supposedly having two parents with almost black hair. Due to her youngest kid having almost blonde hair I'm even more confused.My ex said her first born wasn't mine but that was while she was married to who she thought(or hoped) was the father. She is in a new relationship now do you think she would be open to the possibility of me being the father now? via /r/Parenting http://ift.tt/2gz5Hr1