At what age can you start to breed guinea pigs?

I have baby guinea pigs and would like to sell them before they start to reproduce. At what age should i consider parting them from their mommy?
Answers:
Yes, that's a good idea.
The site at:
http://www.cavyspirit.com/breeding.htm...
tells you the many, many reasons NOT to let guinea pigs breed--give it a read.
As for when guinea pigs start having babies, you'd better sell them fairly quickly. The site at
http://www.guineapigsclub.com/gp_site/br...
says this:
Female guinea pigs become sexually mature at the age of four to five weeks of age and male become fertile at the age of eight to ten weeks. If you want to breed your guinea Pigs the best age to start mating a female is when she is after 4 months as breeding her before is not good and can be deadly.. This the best age for the females as the bones of her birth canal are still flexible.