Opponents to abortion access commonly believe personhood of a zygote begins at conception what is the basis of this belief?

The basis for this belief is that a "zygote" or a baby is a person at the moment of conception. Scientific fact supports that at the moment of conception a baby's gender, hair color, eye color, ect. is already determined. At the very moment of conception everything is already in place for the baby to grow and develop. Check out progression of ultrasound pictures and you would be surprised how rapidly a baby forms. With my pregnancy we saw our daughter's heartbeat at 5 weeks 4 days. Less than 2 weeks after I knew I was pregnant (and I was trying so I knew right away!)

Q: Perhaps I should clarify the question (the question field is too short to elucidate much). Genetic determination begins at conception, but 80% of all fertilized zygotes either fail to implant or miscarry within the first six weeks, hence the presumption that a zygote is already a baby is a misnomer. More logical points to assign personhood (i.e. to establish limited legal rights) would include:

• Eighteen weeks, which is the statistical point of viability. Miscarriages after this point are significantly fewer than ones before, or...
• Twenty two weeks, when brain activity begins, this on the basis that death is legally determined by when brain activity terminates.

So why at conception, when pregnancy is more likely to fail on its own accord than not?

A: Religious dogma is the ONLY defense for the "personhood begins at conception" argument. Generally these arguments are very poorly thought out.

There are really different aspects of being human and they should be clearly identified in such an argument.

1) Basic legal rights - personally I believe these should be vested at viability, when the fetus is capable of living outside the womb.

2) Brain activity - if someone ceases to have brain activity or is born without the capability to function without life support or look forward to a decent life (anacephalic babies are a good example here) their parents should have a legal right to terminate life. This has to be a due process thing because a viable fetus should have legal rights, so it can't be up to the parents alone, there has to be medical confirmation.

3) Spiritual rights - these are the really sticky ones. Religious institutions have made and have the right to make declarations on this issue, but these declarations can not be legally enforced on someone who does not share their religious views. The concept of "ensoulment" must be considered.

Even if you believe that people are a special creation of God distinct from animals and it is the "soul" that makes them so, the question remains: When does the soul enter the body? As you have rightly noted, if life begins at conception, God is the biggest abortionist around.

Ensoulment can not be proven because the soul is not a physical thing, it is a spiritual concept. For that reason, every person who believes in spiritual freedom should respect the right of others to answer that question for themselves.

My personal belief is that ensoulment can not occur without a minimal amount of brain activity, so if I had been raped and could not deal with the idea of having the child, I don't think I'd have a problem with abortion before the 22 week time you mentioned. But that is a personal decision that I would have to make and bear the responsibility for.

Since ensoulment can not be defined or determined objectively it can not be a legal standard of personhood, thus the viability standard.