Is it selfish to choose not to have kids?

Here's the part nobody says out loud: the nurse who will wipe your chin in the nursing home is somebody's daughter. The firefighter who pulls you from the wreck is somebody's son. Every single person who will ever show you mercy in your helpless old age was raised, at great cost, by parents who did the unglamorous work you opted out of. You will accept their care with gratitude while having contributed nothing to the supply of carers. That's a transfer of burden from you to strangers' families, and you know it.