i don't see what the bfd is about last names. keep, change, both change. it's not a bfd.
i kept my last name, and it doesn't bother anyone. i'm the only one among the inlaws with the maiden name. and i don't care that baby mo has a "different" last name -- that's not what makes him my kid.
and it's 2014 AD. a school has seen parents with different last names than the kid's last name, siblings with different last names, kids with grandparents only, foster kids, gay parents, kids with 3-4 parents and foreigners. they can deal with different last names. isn't it enough they have to deal with a kid named ashtalynne?