Making visible embryos is a neat little site that gives a quick overview of the history of the embryo.
I think that pro-lifers should be more involved in studying and diffusing the history of the unborn, as well as abortion. It would provide insight into how abortion was legalized.
I think one of the main reasons why abortion was legalized was the widespread ignorance of the unborn. I know the website says that images of the embryo became more prevalent in the 20th century, but I think that the average person was not exposed to them often before the rise of the pro-life movement and the advent of routine ultrasound.
Of course, the contested status of the unborn was not the only reason abortion was legalized. But without a clear idea of who and what the embryo is, the arguments for legalized abortion seemed much more plausible. When you hear that an embryo is only a blob of tissue or a cluster of cells, it makes abortion seem perfectly reasonable.