"...if we allow abortion, where does it end?..."
Try this scenario...
State of the art genetics allows for cloning, identifying families of individuals who carry certain genetic predispositions.
Here's what's coming:
Soon, all computerized ID cards will carry the owner's complete life record including DNA analysis, etc... .
The "health care industry" will soon have analysed every single individual in the country, and drawn up dossiers on everyone based on "risk" potential.
Expectant parents who register as "suspect" will be offered the ultimatum: either abort the baby, or have your entire familys' insurance cancelled.
All embryos in their mothers' wombs will soon be examined by "specialists" looking for any possible gene sequences indicating a "risk" for developing virtually any disease or problem; even if it is not expected to develop until very late in life.
In the coming socialist world of "single payer" insurance, "universal coverage", etc., all that will matter is "how much are you costing "the community"?
If an individual requires medical care outside of an occasional routine exam, they will be told that they "are damaging our perfect system", and their insurance and "right to health care" will be immediately cancelled by the State.
In addition, the technology will soon present the ability to clone any and all human organs, as replacements for worn out or damaged ones.
Surgery as we have known it, will be a thing for the history books. Instead, most aging or damaged organs will be regenerated through the new miracles of modern genetic science.
Result: The "health care professionals", "associated health-care industries", and "The State", are all going to take a good look around at all the billions of humans now living in overpopulation. They will set quotas allowing only the currently wealthy individuals capable of affording organ & limb regeneration to live as full citizens. All others will be completely "cut off" from all rights as human beings. Some will be actually enslaved, cloned, & mass produced so that they can be murdered & have their organs harvested for use by the rich elites.
Even further: Because the ability to clone life without sexual reproduction will soon exist, and because pre-natal care and childbirth place a financial burden on "the community", sex will be complete outlawed for all except the elite rich few able and willing to pay a tremendous license fee for that luxury. Holders of a sex license will be forced to be either sterilized or injected with long lasting birth control drug devices.
Cloned slaves will function in all servile positions; everything from housecare to manufacturing will be the domain of the clones; some of whom will be genetically engineered to be true androids.
"I've seen the future; and it's murder."...Leonard Cohen