I don't think babies have either autonomy or agency. Their parents do.
So babies aren't actually fully human, they're just sub-human tissue? When do babies become fully human, in your world, and gain human autonomy and agency? Does this apply to all babies equally? Or are there different lines for different people, say, those with developmental disorders, or for different classes or ethnic groups?
I think that is where the fundamental disconnect is, since I and most of us here appear to consider them fully human, and subject to all the rights thereof. The fact that their agency is not fully developed requires that parents supply their own, overriding the child's agency and autonomy on a limited and temporary basis, but only when doing so is in the best interests of the child's life and health.
Any other way opens the door for infanticide, abuse, enslavement, and numerous other atrocities. And before you get all dismissive again, and pronouncing slippery-slope fallacies, history has provided numerous examples of these exact problems. Hell, there are enough of these still existing in the modern world.
And I have another bias to add to the mix. I don't see anything in particular that is sacrosanct about human tissue or the body as it is currently laid out.
And yet again, you're deflecting and demonizing by imputing motives that don't exist. Care to point out where anyone made this claim?
Again, since you seem to have trouble grasping it, it has nothing to do with human tissue or the human body as it is; it is strictly about
individual autonomy and agency, the rights of humans to have control over what happens to their own bodies and lives, as long as they do not infringe on the equal rights of others. It's the most fundamental of human rights. I'm having difficulty understanding why you seem unable to grasp that; and have to constantly resort to manufacturing motives that don't exist.