Aliens lifting quarantine on Earth

Question

I am looking for the name of a short Sci Fi story that I read in the 70’s where aliens welcome back humans to the cosmic community because they have found the cure for people being born white. And it is NOT "Hostess" by Isaac Asimov. It was in a collection of short stories (I think) titled A Space Opera.

Answer 1

This is Reunion by Arthur C. Clarke. The story consists of a message sent by "aliens" to Earth who reveal themselves as the same species and identify humans as the descendants of their own lost colonists from millennia ago. The message explains that contact was cut off (essentially a quarantine) because of a disease that they initially do not describe in detail. They observe,

We realise now that it was a natural adaptation to the end of the long summer, but those who had made Earth their home for so many generations believed that they had been attacked by a strange and repulsive disease. A disease that did not kill, that did no physical harm--but merely disfigured.

Yet some were immune; the change spared them and their children. And so, within a few thousand years, the colony had split into two separate groups--almost two separate species--suspicious and jealous of each other."

The visitors then reveal that they have finally developed a cure that they are willing to share with the people of Earth:

Above all, we have a simple remedy for the offensive yet harmless genetic plague that afflicted so many of the colonists.

Perhaps it has run its course--but if not, we have good news for you. People of Earth, you can rejoin the society of the universe without shame, without embarrassment.

The visitors then deliver the punch line, where they reveal the exact nature of the "disfigurement".

If any of you are still white, we can cure you.