haha....what an interesting topic!
i heard that all the chinese surname, originates from the
emperors'...
So whatever surname you have, your ancestor should be once an
emperor..
dunno whether that is true or not..
so, it means that having same surname, means you originates from
the same source hundred of years ago..
but then again, unless you are related to the person now, i think
its probably ok to get married because recessive genes will be
eliminated by now...
however, i know some parents or elders are still against the idea,
thinking that it is incest...well, your job is to convince them if
you ever want to marry someone of same surname... 