For the most part, this is untrue. The odd part is that those groups that pride themselves on being the "more rational, scientific" group, are ignoring science on the issue.
Here is a short little page which I hope will be useful to anyone who considers themselves "enlightened and rational", yet "pro-choice".
The top 2 arguments in favor of supporting abortion are:
The baby's only real biological connection to the mother ("sharing") blood, is through the umbilical cord. This cord must have special filters in it, to avoid blood from the baby, from triggering automatic rejection mechanisms in the mother's body. The same mechanisms that cause "organ rejection" from an organ transplant from Someone Else's Body
Similar, if the baby is allowed to mature into an adult, and chooses to donate an organ to the mother... anti-rejection drugs are still neccessary... because they are still very much separate bodies!
The baby did not suddenly undergo a generic change at birth... it was always a separate organism during the entire time it was being nurtured by the mother.
Two babies are conceived in two separate mothers at exactly the same time. One mother delivers prematurely, after 6 months. The other one has a full term pregnancy.
The premature baby can barely breathe on its own. Some of them may have to be on a ventilator for some number of days. It cannot properly regulate its own body temperature. It will have to be kept in an incubator for some number of days, if not weeks.
In contrast, a full-term baby, delivered at "9 months" of gestation, will usually be quite capable of breathing on its own. It will also be quite comfortable just wrapped in some blankets, rather than a hospital incubator.
The prematurely born baby, is considered fully human, and alive, the moment it pops out of the mother. To kill it at that point, would be considered murder at any court in the land. Yet it is scarcely capable of sustaining its own life.
In contrast, if you took a look a look at the "full term" baby 1 day before
its official "birth", it would be just as capable of sustaining itself as
the day of its birth. In any scientific, objective method of measurement,
it can be considered more healthy, and alive, than the premature baby,even
while it is inside its mother. Its lungs can function better, it's brain is
more active, and virtually every other organ is healthier and stronger.
To consider the (9-month - 1 day) baby somehow "not alive", while simultaneously thinking the premature 6month one is alive, is the height of unscientific, illogical attitude.