It's officially been 1000 years since the first Marvian came to earth. By most estimations the Marvian population today has reached over 500,000. This is an easily sustainable population for now, but with no known natural lifespan and division roughly every 50 years we will eventually have some difficult choices to make.
Marvians have contributed much to the Earth. From the perfect solar cell to stable wormhole technology it's hard to imagine a world where they had never existed. But like us they need food, water and shelter to function. They may be immortal but that doesn't mean they don't have needs.
But by the end of the century there will be over 8 billion Marvians on earth, barring any unseen catastrophe. While humans have measures in place to prevent the population from once again rising over 6 billion, we have no known way of preventing another overpopulation cataclysm without resorting to the barbaric culling that we had sworn never to repeat so long ago or exhiling our neighbors from the planet they were born on.
John Smith, the first Marvian to arrive on earth, claims that she has not managed to contact any Marvians within communication distance from Earth. Perhaps that will change in the coming centuries, but with no known habitable planets within the fast-communication zone it seems unlikely to happen.
While there has been some discussion of sending a wormhole stabilizer towards a nearby goldilocks planet the cost is prohibitive when there are no guarantees that we'll find any life, no less another Marvian colony that may be able to offer counsel. Prospectors in the asteroid belt are searching for larger deposits of neodymium, but until a more stable source is found wormhole technology will likely stay on Earth.
It's a long way off for us mortals, but I believe it's important to start discussing this issue now so that future generations aren't panicking when this becomes a real problem. I'm not sure there's anyone left on Earth who would truly want to see our Marvian sisters be put out because no one could figure out a solution to the population problem.