User blog comment:Per3ylove/percy jackson/the lost hero/sonof neptune/@comment-3205610-20110210034526/@comment-3160960-20110213094314

They do have DNA, just not among themselves. With mortals, they have DNA. They can marry their sister, or brother, or whoever. Being gods, they may want to marry themselves. Oh, and actually, 2nd cousin. Athena is Percy's cousin, and if you're the child of someones cousin, you're their second cousin. Believe me, I have three 2nd cousins. I have cousins that are older. Not that much older though. By which I mean... well, you know.