[perpetualpatzer]

> You can tell a son that all their male ancestors had a son

This seems off... by counterexample, my grandfather had no sons, but three daughters (one being my mother).

[frankbreetz]

Your mother is not a male ancestor. Parent was just saying there is a line of all males for men and all females for women.

[simiones]

No, but the maternal grandfather is still a male ancestor. Parent said "all male ancestors had a son", which is not true. The true statement is that, for any generation of ancestors, at least one had a son.

[enkid]

I agree that's what he probably intended, but that's definitely not what he said.

[koolba]

Yes that is what I intended. The line up the father side for the boys and the mother side for the girls.