In October Baby, the main character, Hannah, learns that she was born after a failed abortion attempt. Now consider the following.
(1) Hannah is the same being who, at an earlier stage of life, was almost killed by abortion and was subsequently born prematurely and adopted by loving parents. Like all of us, she was once an embryo and a fetus, just as she was an infant, toddler and adolescent. This is precisely the reason for Hannah's distress upon learning the circumstances of her birth, and the distress (two decades later) of her birth mother. To have killed that fetus by abortion would have been to kill Hannah.
(2) Hannah ought to be loved and "wanted" simply because she is Hannah. Her adoptive parents don't love her for her health (which is imperfect and requires serious attention), intelligence, personality or accomplishments, nor for her age or independence. They love her irrespective of these things. They love her for her own sake.
(3) Because the fetal Hannah was Hannah (1), she deserved to be loved as such (2). And since the above two points are not particular to Hannah (each of us was once a fetus; each of us is valuable simply by virtue of who we are), we can extend this conclusion to all fetuses. They are valuable because they are human beings who as human beings deserve to be wanted and loved, regardless of age, size, dependency or any other morally trivial characteristic.
This argument, I suggest, is implicit in October Baby. And it's a good one (go here for more about this kind of argument). Every life is beautiful.