Are sir D's children his actual biological children?

Mostly a head canon thing unless we're told otherwise, but it seems to me that maybe some of his kids don't share enough of his identifying info (skin tone, hair texture, general build, etc) and although D has had many partners, generally your direct offspring are expected to look at least a little like you.

If they are, i wonder if this is a stylistic/character design choice to distinguish them, and if they aren't... well, that just means kitten might get promoted from son in law to son. Honestly with all the recruiting talk I can't help but wonder what plans he has for amanda.