Is it selfish to not give up a kidney because you might die from it?

i saw that movie and in the movie she decided not to give up her kidney beuz her sister who was dying didnt want her to go thru that again so really it was her dying sister who told her to say she didnt want to do it but i think its wrong for any parent to have a child just to save anothers life so is that child suppose to live her whole life giving up everything in her body for her sister who unfortuantly is dying i think its wrong to put all that pain and pressure on a child. and eventually an adult. i felt bad for the little girl because it seemed like they loved there daughter who was dying so much but didnt really about the younger sister who was giving so much