iFamily Support Forums

I'm sure this is simple, but my mind is muddled.

I'm preparing output for my relatives. I'm including a wide range of people. I need to identify people as being direct descendants of FAMILY-NAME, or if they married into FAMILY-NAME.

So what is the terminology???
Direct vs Indirect?
Direct vs In-law
Related vs ?????
Direct vs ?????????

Thank you -
Marion in NY