There are several issues invovled here. Legal and religious and personal. The answers are not the same for all. First religious.
RELIGIOUS:
It is would be proper to include all religions here. But the truth is this is a Christian issue in America. That is because that is the only religion to get involved at this point in time.So, the fundies have always wanted to use the Bible so let's go there.
There is absolutely no meniton of abortion in the Bible and we know that obortoin has been around for thousands of years. So people using the Bible will have to use selected Scriptures and do a lot of interpreting and streching of thier overall convictions to come up with a Biblical answer.
For me I use the Genesis text where God breathed life into Adam. I use the breath of life concept. When baby starts breathing is when I think that the soul enters the body. To me a baby never born alive, never lived and will not be in heaven for eternity. I don't think these pregnancies that ended early regardles of how they ended will have a baby there.
I understand the oppposite view that at the moment of conception there is a soul and so if there is an abortion, miscarriage or morning after pill that there is a baby with a soul that is in heaven. However, from a biblical prespective, the ancients new nothing of sperm and eggs and fertilization and all of that. So it is difficult using the Bible to defend that position as well.
LEGAL:
This one is easy. Throughout the ages, only babies born alive have been recorded as having been born. This is true in all cultures that I know about. We list our birthdates from the day we were born, not the date we were conceived.
PERSONAL:
To me with both the legal line of stating who has actualy lived .so defined and the religious lines so undefined, that leaves only one option for the personal consideration.
The pregnant female. the doctor, the spiritual advisor, the god of choice if you have one and personal beliefs has to prevail here. If the pregnant female wishes to include the male who did the conceiving that should be her choice.
As for as the rest of us. We should bale out of it. It is not our body, it is not our consequences to deal with and we live in a free country. The best we can do is offer support regardlless of the decisin of the pergnant lady involved.
The last thing we need is a bunch of laws on the books regulating this most private matter.