Someone might insist that [identifying them as black] was just plain wrong unless they have some actual African ancestry, insisting on the crazy one-drop rule. But adopted children often take on the ethnicity of their parents, so if you and your husband think of his blackness as in part cultural, he is surely entitled to pass it on to his children....And:
The fact is that our system of racial classification is based... on a mélange of falsehood and ignorance — with, no doubt, an occasional admixture of truth.The answer is so complicated, but I think it means (should mean?): As long as there's some aspect of truth in the choice, choose what makes you feel best.
IN THE COMMENTS: A lot of talk that strains for scientific truth, leading me to say:
The reason this woman was asked about the race of her children was cultural, not genetic, so she should feel fine giving a cultural answer.
The only serious ethical problem that arises is if by claiming one thing and not another, her kids deprive someone else of a benefit.
Choices that strengthen the bond with the father are basically good. Why should this family have to be transparent about how these children were conceived? The highest value should be placed on family love and happiness, as long as they are not hurting anyone else.
That's how I would uncomplicated this.