Humankind is bound to become a space-faring species, expanding beyond the bounds of Mother Earth, just as it, millions of years ago, spread out of its cradle in Africa.
At least that's what space exploration leaders such as the world's richest man Elon Musk would like you to believe. However, there may be biological hurdles that could forever confine this vision to the realm of science fiction and human civilization to our Earthly soil. A new study found that sperm cells of mammalian species including humans, mice and pigs struggle to find their way through a female reproductive tract in microgravity to reach and fertilize an egg. Even when the sperm makes it to its destination, the study found that embryos formed in these conditions develop poorly compared to those evolving in normal gravity.
