"We should likewise not apply human rights to a developing life form that does not have a brain."
Ok, so no brain, not human..... yet. But if left to develop, it will soon become human, at which point it WILL have human rights. And by messing around with it you're robbing it of its potential humanity.
Ok so you've misused the terminology here.
"
Ok, so no brain, not human" is incorrect. The developing body, as already stated upthread has human DNA and thus is of human species, Homo Sapiens. It IS Human. That is what it is to be a human. A life form with human DNA.
But it is NOT a person.
"But if left to develop, it will soon become human, at which point it WILL have human rights"
It will always be
human because it has human DNA. If left to develop, it will eventually become a
human person at which point it will have human rights.
So the core of the matter is the point at which is goes from being just a life form with human DNA to becoming a real human person.
That point, I submit, is once a functioning brain has developed, not before.
"And by messing around with it you're robbing it of its potential humanity."
Yes, if you terminate an early life form of human species or indeed any other species you are preventing the potential resulting product from appearing later on. But think that through. If you think it's wrong to terminate a human species life form that is NOT a human person then you need to be consistent and apply this throughout.
That means that every single sperm currently sitting inside a man's sack, is to be given human rights. Not one can be terminated for every one of them is of human species with human DNA and every one of them has the potential or possibility to develop into a human person later on.
Similarly every female egg in existence would also need to be assigned human rights and so it would be murder to do anything that would or could adversely impact those eggs. That means drinking alcohol or smoking for example would have to be deemed potential forms of murder of female eggs. So too taking drugs and so on.
All of that is of course patently ridiculous isn't it?!
In fact humans are designed in such a way that the male sperm, by design, lives a certain time inside a man and then perishes still inside the man and then gets replaced with new different sperm. That's a rolling continual process. By Nature, by design, LIVING HUMAN SPECIES sperm will die, perish, be terminated completely naturally irrespective of the fact that every one of those sperm has the potential to eventually become a human person. The same is true of female eggs.
So this is why it is absurd to look at mere human species life forms and think of them as people or persons before they have developed a functioning brain. They simply are not people or persons at that point. They have potential, just as sperm and eggs do, but applying human rights to things that are not people is wrong and very silly.