User blog comment:It-Freaking-Melts~11!!/New Characters for Sons of Neptune Decoded/@comment-4388581-20110905232558/@comment-3146930-20110905235202

Roman demigod children start their journey at the Wolf House, if they are strong, Lupa takes them to camp and if they arent, she eats them. If Frank's mortal parent died, he would have never made it to the wolf house and would most likely be dead. If Artemis/Diana (a goddess that doesnt like men) did take pity on him, she would just take him to the wolf house and his own parent could claim him.