Re: The quills are falling out!!
Outside of pregnancy risk, another very important reason they should not be allowed to play together is that females are induced ovulators. Meaning that they do not have a cyclic cycle like many other mammals, but ovulate when in the presence of a male. There has been some concern that when a female is constantly in the presence of a male she will ovulate frequently, and could possibly increase the risk of reproductive cancers later in her life.
Also there is concern that having a male so close to a female and to not be able to do what nature has programmed him to do (mate) that it can frustrate the male. Which isn't quite fair to the male hedgehog.