I think
Kieran would SUIT girls more than boys in sound 'cause it's so close to
Karen and sounds girly. Doesn't mean it's a girls' name rather than a boys' name, but it still sounds more like a girls' name than a boys' name imho... not that I'd use it on either. First time I encountered that name, I wondered why the parents had inflicted the boy w/ such a girly sounding name.