The root cause of abortion is Sin.
I disagree.
I don't even see how those who are strongly opposed to abortion can accept this statement, because it becomes for them a circular argument. The cause of 'sin' is 'sin'. Not terribly helpful, is it? And how are we not to sin? Don't sin? Hmm, doesn't do much for me, given that there is not one of us on earth who is without sin, or who can remain for a day without sin of thought, word or deed. So circularity adds nothing.
It is tempting at times to use this kind of soundbyte statement, but it is far too simplistic and has the same substance as candyfloss. (Cottoncandy for our US friends.) Looks good, but melts to nothing when you try to derive goodness from it.
Unwanted pregnancy is not always the result of sin. Sometimes unwanted pregnancy happens within marriage. Sometimes it happens when the family find out that the child is severely disabled, and cannot face bringing it into the world. Less happily, imo, it happens when the family find they have another boy on the way and already have four boys. I have known this situation, and I found it very difficult to accept, but it happens. It even happens as a result of rape. Or is a raped woman or child a sinner even if she aborts a child? That is a position I cannot accept, even for the sake of a nice and tidy black and white world of clear cut sinners and redeemed. The world simply is not on that Janet and John level of functioning. Good luck to anyone whose mindset is.
I personally think it does Christianity no favours to take this polemic point of view on anything, least of all matters of personal conscience, and personal morality. There but for the Grace of God go any one of us, and we really need to use prayer and love in our words and our thoughts, rather than blanket condemnation, imo.