the legal requirement is that you tell them how many people are living at the address. The rest of the stuff is illegal according to all the anti-discrimination laws. They shouldn't be able to ask race, creed, etc. We always write in, 2 american citizens live at this address, or however many there are depending on the kids and such. Screw the rest of their questions, they don't need to know.
As for the geneology angle it may be neat to have the info from way back but its being used against us, meaning all of us regardless of color. They have no reasonable or useful reason to have that info. Screw em.