One of the justifications for the ultrasound requirements that some states (including Idaho) are considering is that if women considering an abortion, seeing that the "fetal tissue" looks like a very, very small baby, and has a heartbeat, may cause some women to change their minds.
One of my readers pointed me to this, which reports that 72% of women who were planning an abortion change their minds after seeing the ultrasound. I am a bit skeptical, partly because this survey was done of women who had gone to a pro-life pregnancy counseling service--where I would not expect women who were terribly committed to abortion to go. It would be like doing a survey of people going to a steakhouse, and discovering that a large fraction were committed vegetarians. In addition, this is only a press release, not the full study.
I am curious to see studies on both studies of this--but I am not finding much actual data on either side of this. If you know of any, please let me know.
UPDATE: Never mind, found them.