Scientists in Japan have found that microgravity may function as a form of birth control. Hence it will be difficult to conceive in space. There goes our hopes and dreams of populating on space ships and other planets!

According to a paper published in Public Library of Science ONE, the obstacles that mammalian creatures go through are not as great as opposed to reptiles and sea urchins. Which pretty much explains aliens looking like how they do?

The Japanese biologists investigated the low gravity effect on mammals and tested them on stored mouse eggs and sperm inside a three dimensional clinostat which mimics the effects of weightlessness. Fertilization only occured normally in the simulated microgravity, but the embryos that were developing in the clinostat had a difficult time maturing than those in normal gravity.

Only some of the embryos survived but they were in lower numbers. Which suggests that our reproductive system may be especially sensitive to gravity. Is this a form of population control?

Making Babies in Space May Be Harder Than It Sounds [Wired]