Possibilities

The call that she expected, never came.

She knew that this wasn't really something to celebrate but she was really happy that she didn't receive any calls from her father or mother or even Grant. She turned off her phone and looked at the sparkling cityscape from her condo unit. 

It was already ten in the evening. She would wait until tomorrow for her father's call. After that she would use Jane to help her search for her birth parents. Right now, her options weren't really a lot. She knew that her father was on only son. But the fact that she looked like him cannot be denied. 

So, there are a few possibilities. First, it's either, this was all but a coincidence. She looked like him because of some rotten luck. Second, she was the daughter of his brother or sister that was hidden by his family for some unknown reasons and third… she was the daughter of her grandfather— her father's father. Meaning, she was her father's sister.