I suppose in theory you're right, Daniel/Chaka could work (or Chaka/Daniel for that matter.) I think just because humans beings (in general) have Xenophobia and the idea would cause the squick factor for a number of people.

Then again if a spaceship landed crewed by blue, green or people with cat ears/tails asking for help in repopulating their species with lots and lots of sex (afterall artificial insemination just won't do!) I suspect a *huge* chunk of our population would take up the gauntlet.