Reply #4: You could always use something like Icelanders use... [View All]

[Interrobang]

In Icelandic tradition (following the conventional and not modern pattern, which is exclusively patronymic), nobody changes their name when they get married, so it's not uncommon for everyone in a family to have a different last name. See, if Ragnar Jorgenson and Dagny Heithrsdottir get married, and have two children, a boy and a girl named Erik and Brynja, then Erik's whole name would be Erik Ragnarsson and Brynja's would be Brynja Dagnysdottir.

So, a good compromise solution for dual-name couples might be to give children the last name of the parent of the same sex.