"You don't want children? That's stupid! If your parents thought that way, you wouldn't be here!" - Ever heard something like this? It's a completely fallacious non-argument that has zero logical merit. Let me explain with a story.
Stacey has a precious gem. She suddenly decides to throw her gem away. Amy finds the gem, and Amy is now rich. Amy is very happy! However, Brad comes over to Amy, and tells her: "You should throw your gem away Amy! If nobody threw gems away, you wouldn't be rich now!" Who is stupid here? Amy or Brad? Because you sound like Brad if you use this non-argument. If A led to B, and if B is useful to you, saying it would be logical for you to commit A is a fundamental error in reasoning. It goes somewhat like this:
"A acts in a way that has several consequences, one of these is B.
B benefits you, so it is rational to copy the actions of A"
It is very easy to demonstrate why this argument is fundamentally flawed:
"The barkeeper gave me back too much change! I now have more money, and I like this, thus it must be rational to give people back too much change."
Let's disect the logic of this argument:
(The barkeeper) - A
(gave me back too much change) - The action done by A.
(I now have more money) - B
(I like this) - B benefits me
thus it must be rational to give people back too much change - flawed conclusion
Let's do another...
"My sister killed herself, and now I inherited her house. I like owning a house, so I should kill myself."
(My sister) - A
(Killed herself) - The action done by A
(And now I inherited her house) - B
(I like owning a house) - B benefits me
(I should kill myself) - Flawed conclusion.
So let's now put the original flawed argument in this form.
"My parents had children, so I'm alive now. I like being alive, so I should have children."
(My parents) - A
(Had children) - Action done by A
(I'm alive now) - B
(I like being alive) - B benefits me
(I should have children) - Flawed conclusion.
Etc...
Now I understand some of you like having kids. That's completely fine. But please, do not use this argument as if you somehow have some kind of intellectual nugget of wisdom that you ought to share with the world. It's a shame childfree people have to listen to this.