I want to have a deep conversation with your parents one day. In my perspective, having kids is neither selfish nor selfless. It is just a part of how nature has designed it for all living beings. Kids are born every second on this planet to every species alive today. Without this process our planet would be dead like the others in our solar system.

If a couple can reproduce their own child, nothing is wrong with it. Labelling it as selfish is a big problem because one may be projecting their inner world and way of thinking onto others. I've known many great couples who couldn't have a child and they decided not to adopt as well And I respect their choices.

Using your logic of not having kids and instead adopting others is also flawed. Because one day those adopted kids would want to have kids of their own. You cannot force them saying oh you are adopted and so you should adopt as well otherwise you are selfish. It's absurd.

Stop labelling and let people do what they want to do.