It’s not about that, you are personalizing a universally human condition to be right. Let me just get you to the other side of your question: why do people want to have children? Let’s ask the justification question from the other side.
I’ll start with some personal stuff: I’ve never been moved more powerfully by anyone over my children. I think it’s in the DNA, we procreate and we are sincerely in love with our creations. It’s the kind of love that mesmerizes us and follows us and consumes us. For years and years we are romanticized by this love and we will go to the ends of the earth to make our passion worthwhile. We continually work for and teach our offspring. We want them to be brilliant, beautiful ad successful. We will invest millions in our offspring’s life to assure this success.
Parents are, however, very clumsy. Sometimes we do a good job and sometimes we do not. Sometimes the DNA is just not going to work and our child may have handicaps, both seen and unseen, such as mental illness or developmental disabilities.
I think what people are really saying to you when they question your decision to not become a parent, is this; you will never find a greater love, a greater task and a greater challenge. You will be forced to learn all kinds of things that you have no interest in knowing, but you will learn because you have to. You will be motivated in a way that you cannot now imagine, but once you are there you will not know how life was life without your child. It is a giving that has no boundaries and a taking that does not end.
If you do not have a child, you don’t get the experience. It is possible that other experiences will be just as wonderful and just as awe inspiring and just as enduring. Parents just want you to know that you might be missing something.