Space agencies the world over have done rather extensive experiments, to see if outer space is as bad for the lower front qudrant as it is for the rest of the body. It looks like the answer is yes.
Traveling through space isn't easy. The low gravity reduces bone density and destroys muscles. Cosmic rays stuff people full of radiation. Biological functions, which are usually assisted by gravity, become physical and engineering challenges. Agencies around the world have looked at the physical damage that bodies take in space travel and uncomfortably crossed their legs when they thought about copulation. Then they decided to start testing.
Obviously, hoping to destroy the fertility of the best and brightest, or sending pregnant women to space wasn't an option, so the scientists started with animals. Lab rats that have traveled extensively in space have lower sperm counts and lax, lazy ovaries. In the late seventies Russian scientists, perhaps inspired by the loose morals of the time, sent a male and female rat into space with astronauts to see if there was any barrier to conception. Apparently the biggest barrier was mood. The rats weren't interested in getting together. The need to take the "will" portion out of the experiment led to astronauts traveling to space with little packets of fish and frog eggs and fish and frog sperm. The eggs were fertilized successfully, and even hatched, but the frogs never developed past their awkward tadpole stage.
It's the rats that are the most troubling. Two weeks of space flight rendered the rats infertile. Although it does not seem to have the same effect on humans - many astronauts have children after returning from space - details are sketchy. Nasa has been reluctant to turn over sperm. However, there are ways to combat muscle and bone loss in space. What would it take to keep the reproductive system online? Two comely alien lasses and a Captain Kirk uniform? Brent Spiner? Only more testing will tell.