There will be no white people left in UK because people are marrying and having babies with other races so it'll be the white people that are the ethnic minorities.
Also if every one ends up gay no babies will be made naturally (you know male and female intercourse)
For gawd sake.
We were all black skinned once many thousands of years ago.
As black skinned humans migrated north over thousands of years from Africa , we evolved to have white skin due to climate.
In the same way if we reversed process and migrated slowly back towards equator , in a few thousand years we would evolve to be b;ack again.
No such thing as race on humans either.