Fail.
The ovum, once fertilized, ceases to be an ovum. The two gametes (ovum and spermatozoon) form a zygote. The zygote is the first stage of human development. We start out as a single cell. Then comes cleavage and we become two cells. Then four, then eight, then 16, and so on.
Did they not have sex ed when you were in school? Go to the library and ask for a book on embryology and human embryogenesis.
If killing some people is okay and killing others isn't, what is the difference?
If it has something to do with the person's age, then at what age does killing you go from being an okay thing to a not okay thing? At what point does what change that makes killing you in cold blood no longer okay?
We are debating your contention that the fertilized egg is absolutely the same thing as an adult human.
You have offered no similarity other than the genetic material in the cells. That is an immaterial difference.
Remember, you said using RU486 was no different than killing a born human.
That is absolutely false, since there is no material similarity between a fertilized egg and a born human.
You have offered nothing material to prove they are identical. In form, a fertilized human egg is far more similar to the fertilized egg of many non-human species than it is to a fully grown human being.
The case for declaring the killing of that fertilized egg to be no different than the killing of a born human is without material support.