It would still be selfish, but at least the child would have one parent, his mother, who would be no more than two generations older than him or her by dint of simple biology. This child's youngest parent will be an OAP when he is an adolescent!
This is all about circumstance.
Elton didn't meet David until late in life, so why should he be denied the chance to be a father? He could well have had a child when he was married to Renate, but it would have been a bit of a fluke, and a band aid child too.