It turns out that this issue is not to be left for future generations. Labs in California and Great Britain, at least, are creating human embryos in various ways. The upshot being that an embryo is an embryo. I believe the Catholic Church is way ahead on this - Every Sperm is Sacred, after all:
The process “involves creating human lives in the laboratory solely to destroy them for alleged benefit to others,” said Richard Doerflinger, spokesman for the U.S. Conference of Catholic Bishops.