Which Father Should You Ask?
There is one further complication you may have to consider if your girlfriend has a biological father and a stepfather. Which one do you ask?
The answer to this question depends on individual circumstances, but generally you should ask the father that has played the biggest role in her upbringing, and the one she is closest to.
If her parents divorced when she was very small and she has lived with a step father for most of her life, he is the obvious choice, especially if she is closer to him than her biological father. However, if she has an equally good relationship with both fathers, the biological father usually takes precedence.