It's not illogical - it's simply an extension of the fundamentalist argument that is being proposed against IVF.
Some are drawing a distinction between facilitating conception and facilitating extended life through medical techniques.
I offer that life is life and there is no distinction between a sperm and an egg and you.
Therefore, if medical intervention is bad it is bad in all cases - I think to selectively select areas where it's ok completely invalidates the "it's God's will" argument.