I don't have kids. I have not caused a need for me to die to make room or to be "replaced" (though "overpopulation" arguments are often eugenicist and/or racist propaganda, and don't engage with actual density/agricultural limits, so I'm hesitant to make any arguments based on whether there is room for people to not die).

How can you want for other people what you don't want for yourself? Why should other people die, for example of cancer, when having the chance I'll opt for the cure?

Obviously not? What an insane question

do these other people have a fertility rate of at least 2.1?