Is sacrifice a necessary part of parenthood?
Some parents are involved in a sacrifice when they choose to have children. If they do it for no good reason, out of duty or as some kind of old age insurance.
In my opinion rational parents choose to have a child because they have a vision and want to create the best human relationship they possibly can with a child. Don't confuse challenges involved with raising the child as sacrifices. Just like you might have challenges in your ideal career or in romantic love there will be hardships raising a child. But self imposed responsibility is not a sacrifice if the higher goal is rational. The higher goal is the unique kind of human relationship only possible between a child and a parent, the values and joys it brings to life.
No sacrifice is involved in a healthy child parent relationship. Only self chosen responsibility from the side of the parent. In fact I would go as far as to claim it is impractical to consistently sacrifice in a child parent relationship. It will most likely turn into something unbearable for both and end bad.
To love is to value. "self-sacrificial love" is a contradiction and is impossible. Hopefully most parents value the children they choose to raise. No child would like to be considered a sacrifice. Just like no man or woman would like to be chosen as a sacrifice in romantic love.
Is it impractical to consistently sacrifice in a child-parent relationship if the child is disabled?
Sacrifice is to surrender a value and expect nothing or less in return. Consistent sacrifice is impractical in any relationship.
Then are you suggesting that it is impractical to be in a child-parent relationship if the child is disabled?
Disability or not is a nonessential. It is very contextual. If it's impossible for the parents to find value in the kind of relationship possible to create with the disabled child it can be. But disability can take many forms and does not have to make it impossible for the parents to gain a huge value in the kind of relationship possible.
With that said. I can think of situations where it would be perfectly moral to give up the child to an institution or if possible get an abortion to prevent any long range sacrifice. It can destroy your life to take on a long range sacrifice.
So now you're saying to be in a child-parent relationship if the child is disabled can possibly even destroy your life?
Yes. Consistent sacrifice will destroy your life long range.
"It can destroy your life to take on a long range sacrifice," is a philosophical statement that makes some presuppositions that need to be defended...as well as some terms that need to be defined. It assumes complete sacrifice to the point of physical and mental exhaustion and to the exclusion of happiness cannot be meaningful, important or even be done joyfully. Notice that there is a difference between happiness and joy. Naturally you are making some assumptions about fulfillment, ultimate meaning, and so forth. In short, you perspective is quite true from a humanistic, self-centered perspective. If however, the truth is that there things more important than self your view is incorrect. I believe this to be the case.
As for it being morally acceptable to abort a child for your own gain, this also presupposes that your happiness is more important than that of anyone else. To make that assumption while claiming moral high ground is untenable to me.
Edit #2 I just noticed your tags. That explains a lot. Her views are interesting, but ultimately shallow and untenable. It has been some time since I have read her and studied objectivism, but it is not one of the more comprehensive, coherent, comprehensive, and congruent worldviews. How a worldview stands up to these "c's" is a good litmus test for it's preference I believe. Of course it has been my experience that debating an objectivist is doubly difficult because of what I would consider the major tenant...selfishness. Who does not want a worldview that says that it is not only ok to be selfish, but preferable and morally correct? Nonsense.