it all depends on what you consider ethical.
for christians, ethics are rooted in the holy bible.
for atheists, ethics are just a construct of an evolved human brain, the chance product of random particles bouncing around haphazardly in a purposeless environment.
one is eternal, unchanging, necessary, universal, and certain.
the other is relative, subject to revision based on society's whims.
for example, christians will always believe it is wrong to kill a 5 year old with downs syndrome.
atheists, however, will say that someday it may be okay to kill a 5 year old with downs syndrome if society collectively decides it is okay (e.g. eugenics).
choose your side wisely.