According to my personal bible, this is Psalm 51:5
"Behold, I was brought forth in inquiry,
and in sin did my mother
conceive me."
I fail to see how this supports the personhood of a fetus. The Fetus is not talking, unless I've misunderstood the Psalm. Rather, he is talking about the past, where his mother, presumably out of wedlock, fucked a dude and got in trouble. I don't see at all how this supports your claim.
Again, according to my bible Psalm 22:10 states
"On you was I cast from my birth,
and from my mother's womb you
have been my God."
The first line clearly doesn't support your argument. Now, if we take "from" to mean "since", which I think is reasonable, he's saying "since I was in my mother's womb, you have been my God." But, does this mean since he was conceived? To me, that is not at all clear.
Luke 1:44 is a bit long; hopefully, I'll have time in the future to address it.
In the mean time, I'd like to ask you about the following Psalm 137:9
"Blessed shall he be who takes your little
ones
and dashes them against the rock!"
To me, this indicates that it's OK to kill someone's children if they've wronged you.
So, please tell me: If the Psalms are to be used to loosely justify preventing abortion, why is it not ok to also use them to justify killing real babies of your enemies? You'll note that we are both referencing Psalms and, quite frankly, my verse much more clearly supports my 4th trimester baby killing that your no abortion position.