Has NASA (or any other space agency) determined if human eggs can be fertilized in space (specifically in zero-gravity settings)?

I read last week that there is some doubt if human kidneys would perform properly on space travel to Mars. (see this article) – which places some doubt about how long term space missions would take place.

Along the same lines: for long duration space travel – has there been any research on whether human eggs will successfully be fertilized in space? In low gravity or no-gravity situations?

Would that be an impediment to exploring other planets and galaxies?