I came across this interesting exchange in an article at Orthodoxy Today:

"A number of years ago, a woman called on the writer, stating that she had become pregnant much against her wishes, and earnestly desired that an abortion should be produced. The following conversation ensued:—

“Why do you desire the destruction of your unborn infant?”

“Because I already have three children, which are as many as I can properly care for; besides, my health is poor, and I do not feel that I can do justice to what children I now have.”

“Your chief reason, then, is that you do not wish more children?”

“Yes.”

“On this account you are willing to take the life of this unborn babe?”

“I must get rid of it.”

“I understand that you have already borne three children, and that you do not think you are able to care for more. Four children are, you think, one too many, and so you are willing to destroy one. Why not destroy one of those already born?”

“Oh, that would be murder!”

“It certainly would, but no more murder than it would be to kill this unborn infant. Indeed, the little one you are carrying in your womb has greater claims upon you than the little ones at home, by virtue of its entire dependence and helplessness. It is just as much your child as those whose faces are familiar to you, and whom you love.”

That's a very good point. Isn't it odd that on the one hand human helplessness justifies exorbitant social welfare programs to ameliorate the suffering of the poor and the disabled and those who generally cannot scrape by on their own. However, an extreme form of that helplessness in the form of an unborn child is precisely the reason many give to justify extinguishing that life.

Honestly, those who make claims about the dependency of the unborn on their respective mothers should take a look around. All people till at least the age of fifteen are helpless in their own way: physically, to the extent that the young cannot make a living for themselves, and psychologically because the complexity of our societies takes years to comprehend, let alone master. Try finding another creature with as long a childhood as humans enjoy.

Abortion proponents make a fundamental mistake, confusing essences and accidents. For some reason they want to claim that physical size, development, etc. are all determinative of one's humanity. How is that any different than Hitler claiming that those with hooked noses or those doomed to spend life in a wheelchair are fit to be destroyed?