Which variables should I use in my data extract for determining father-son pairs?

I am doing a research on intergenerational mobility and trying to obtain the father-son pairs for determined years. Which variable I should include in my study to match them?

Matching father-son pairs together can be done a couple of ways with IPUMS USA data. First, you can link parents and children with the Attach Characteristics tool, available on the Extract Request page. This allows you to build a data extract with parent information linked onto each observation of associated children. Second, you can use the family interrelationship variables, such as in your case POPLOC, to make these links yourself in your data. Both methods should produce the same results.

Thank you so much for the response! I am so sorry I accidentally hit the thumbs down button.