A few questions before giving definitive advice...

Will you be recording EXACTLY the same sort of information (e.g. name, address, dob) for Father and Son, or will one have more/less information than the other (e.g. only record Marital Status for Father)?

Can a Son have only one father (not biologically!!) e.g. would you need to record both a natural father and a stepfather.

Can a Son exist without a Father?

Can a Son also be a Father?