Im not exactly opposed to abortion, but i dont have a proper answer on this.
If we could conclusively say abortion is the end of a human life, then all arguments
for abortion ought be juxtaposed with that fact. Ultimately you will find it is always a killing of convenience, a murder
I dont think that even if this universal law would be a thing, none of us would conclusively know
Calling it a "universal law", is really just a fancy, perhaps misleading given what people think of when they hear "law", way of describing this fact:
All things that
exist, have a form, which determines what is the final end for said thing, and this "end" determines what is good/bad for it.
For example, the form of a lion is to be carnivorous, a final end which is realized perfectly whenever lions eat meat; the form of a dog is to have 4 legs, so a dog with 3 legs necessarily "fails" in this respect so it is a "less perfect" dog
Everything that exists has a form, and so within every thing that exists there is a "perfect" degree of it's aspects.
As rational creatures, humans have a final end to always choose what is rational. This is what is meant by "universal" law, this principle which humans have as an end of their nature to always do what is good
This universal obligation humans have to perform good actions, is a truth related to the
form or essence of the thing (humans), just as 2+2=4 is a necessary truth related to the very form of 2 + 2 equaling 4
And so it is a
conceptual truth we can know by reason alone, it cannot be proved by observation of cultures or any data. It is a fact based on the form of the thing, like 2 + 2 = 4