I saw this movie about 15 years ago on TV when I stayed home sick from school one day. It was about a girl who was kidnapped by a couple who raised her as their own child. I don’t remember how, but when she was in college she somehow found out that she had been kidnapped. She does her own investigation, and finds her real family.
The thing that stands out to me most is that she had red hair, and when she meets her real family, they all have red hair too, even the mom and dad.