Frozen Embryos, for what purpose are you speaking of? Some purposes are evil and some are just selfish. Vitro? I do not have an opinion, I have never really contemplated it.
If morality is not a constant, is not an outside authority beyond mans corruption then we have only to look to the morality of Hitler to see what can be justified and agreed to by the majority. I believe some of our Founding Father wrote and spoke about the inevitable failure of even the best form of government if the people choose to not hold to certain moral standards and to a common belief that all men are Created equal, with certain in-alienable (Creator given and thus out of the reach of man) rights.
All men Created equal, with certain in-alienable rights. Is that just a nice thought of man? If so then our so called rights in reality amount to nothing more than those of the lion or chimp. They can be changed, reinterpreted or removed with no in-morality applied. If our rights are nothing more than an idea, we cannot legitimately call Hitler wrong, let alone evil. That would only be our opinion, not fact. Just a thought subject to interpretation. If our rights are nothing more than an idea, they are in-fact government given and can be government taken away.
Further, if you and I are nothing more than animals whose ancestors evolved through time; I would submit that all men are not equal and that anyone can conquer or kill with full moral immunity or superiority. That calls into question any form of governance not directly agreed to individually. And even then, would it really be immoral to resend from such an agreement.