What's the Latest Development?

A forward-thinking department in the Pentagon held a symposium last week to discuss problems posed by interstellar space travel. Among the topics discussed by the Defense Advanced Research Projects Agency was the problem of procreatin in space. "A trip to even one of the closest stars would take decades and possibly hundreds of years, likely spanning multiple generations. But scientists aren't even sure humans can procreate safely in the microgravity of space." Earth's gravity is necessary for healthy muscles, strong bones and good vision. 

What's the Big Idea?

The star nearest our Sun, Alpha Centauri, is four light-years away, which means it would likely take a space ship a few decades to arrive. But the necessity of procreation in space remains an obstacle which we do not have the technology to overcome. Let alone what to do when humans arrive to a foreign solar system. Assuming there is a rocky planet we could land on, how would we survive the new world? Terraforming an atmosphere is one option. Another is engineering our biology to suit a new environment. That might create two distinct human species, incapable of breeding with each other.