non bredding piggys?

Question
Hi katie.
I got my piggies about 5 months ago from a petshop outside of my hometown.  They were around 3 weeks old when i got the pair, and i asked specifically for two piggies of the same gender.  However, i now know that they are infact a male and female pair.  What confused me is that they have never bred, or shown any interest at all in breeding.  When i saw them in the petstore they were together in a cage, and i beleive they had a litter of them they were selling.  Would the fact that they are brother and sister and raised together have anything to do with this?  I do not want to sperate them because they seem to realy enjoy each others company.  For example, the female panics and squeals when i take the male out, and she cant see him.  Anyways, im awaiting your answer, i want whats best for my piggies, thats all. thanks for your time.  Marie.  

Answer
Being brother and sister has nothing at all to do with it. Are you sure they are infact male and female?
www.cavyspirit.com/sexing.htm

Please separate them NOW and have the male neutered. Even though she hasn't got pregnant yet, you do not want her to after she is over a year old or she will have major complications that can end in death.