If organ transplants are ethical then there seems to be no grounds on which to object to use of embryonic cells. The real question is surely only how embryos are obtained.

The real question is surely only how embryos are obtained. — Barry Etheridge

This.

But the way that they are obtained doesn't change the fact that they are alive.

They are alive in exactly the same way as transplanted organs, masses of living cells which are not self-sustaining. If it is ethical to use one for medical purposes then it is ethical to use the other. It really is as simple as that. Thus the only ethical questions that need answering revolve around how the embryos are obtained; consent for in vitro fertilisations, time limits on stored embryos, whether aborted foetuses might be used without consent and so on.

What confuses me the most in these kinds of situations is that who decides if something is ethical or not, I believe it is the society. Apparently, what most of the people agree on is counted as "ethical". However I sometimes happen to disagree with the decisions of society on these kinds of topics. Producing a living organism to kill it doesn't seem ethical to me but we cannot unsee the benefits of these products. Obtaining embryos in laboratory conditions sound unethical to me but I agree with you on using the unwanted embryos taken by abortion with the consent of the mother for therapeutic purposes being ethical.

Is it ethical to use embryonic stem cells to cure diseases? Which of these stem cell types are best for therapeutic usage? Embryos don't have emotions or any life experiences, should it really be considered as unethical using their stem cells have many benefits while curing diseases? — verbena

Yes, it is perfectly acceptable to use embryonic stem cells to cure diseases. To view it as wrong is to place more value on a someone who doesn't even exist than a fully-fledged person who is suffering. In other words, the mere idea of a future person is not important, unless of course this person is going to exist and suffer themselves.

In my view, it all comes down the instrumentality, i.e. the harmful utilization of other sentients for the selfish benefit of others. An embryo is not a person and thus cannot be instrumentalized. Nor is the person the embryo is set to become existent yet. No crystal ball predictive magic shit here; focus on the here-and-now, the people who actually exist and who are actually suffering.

Ethics in a world like ours should be focused on janitorial clean-up duty; figuring out ways we can clean up the mess we're and with the least amount of harm-trangressions as possible. If we end up maximizing happiness and becoming virtuous sages along the way, cool, whatever, but that shouldn't be our goal. So it's not surprising when I dismiss the potential future good life of a person as irrelevant.

who decides if something is ethical or not — verbena

Hospitals and research universities employ ethicists and panels of experts to assess the ethics of various procedures. The various institutions of society (religious, secular, political, academic, etc.) also engage in ethic-definition.

We may not reach a society-wide consensus on what is or is not ethical. In which case, we have lots of disputes, laws, punishments, disobeying laws, and so on. Whether destroying embryos is ethical or not is not settled.

An embryo produced by stimulating an adult cell into becoming a pluripotent stem cell is too 'manmade' to be considered the same as an embryo produced by the usual sperm/egg method. So, I would consider it ethical to use or destroy the embryo, as needed. Should organ tissue be generated and grow into liver, that too could ethically be used or not, either way.

If an adult-cell-derived embryo is implanted in a womb, begins to develop into a normal fetus, (I don't think this has been done for humans yet, or yet reliably) then it, as a prospective person, could not be aborted, except under ethical rules (like, after 24 weeks of gestation). I also don't like the idea of aborting otherwise healthy fetuses for the purposes of obtaining tissue for whatever purpose.

The whole business of cloning and genetic engineering of humans is unsettled ethical territory, too.

who decides if something is ethical or not, — verbena

Individuals always do.

Those individuals can agree or disagree with other individuals, and this winds up impacting whether something is allowed practically (via mores/customs/social censure/etc.) or formally (via laws).