> making the kidney effectively 100.

And then some. They start working in utero, roughly at the end of the first trimester I think.

thanks for the clarification, still fascinating that the organ could live that long .. what if the son gives the kidney to a teen again ?

That won't happen. Even though it's still adequate for him it's very likely preforming under what a typical healthy kidney performs at. Long term slow rejection is nearly impossible to eliminate. No kidney transplant is forever and only in truly exceptional cases does it last the lifetime of the recipient.

> only in truly exceptional cases does it last the lifetime of the recipient.

Well, sometimes they do, just not the way we’d hope they did…

> fascinating that the organ could live that long

All types of organs can live that long, there are 100 years old humans around. Probably many types of organs could live much longer, we don't know that, the humans having them die first.

I didn't read the article, apologies, but did they say the kidney was under-performing ? my comment above is badly trying to say "it's 100 and about to go much further"