Both females (sows) and males (boars) can be neutered. Costs for neutering guinea pigs vary, but the operation will normally cost around $60 per guinea pig. Bear in mind that you'll only need to neuter one of the sexes if the aim is simply to prevent unwanted pregnancies.
Sows can be neutered via a sterilization injection, while boars require a surgical operation. But is the operation actually necessary?
Any operation is stressful for a guinea pig and not without its dangers, so if possible you should keep guinea pigs in single-sex combinations. This precludes the possibility of GP babies; although remember that segregation should never result in a single guinea pig being kept on its own. They always need company.
A Teddy guinea pig looking for a new home
Female guinea pigs can become stressed when pregnant, and when confronted with hungry youngsters. Severe birth complications are not uncommon either. So, if you want young guinea pigs it may be best to consider adopting them. At any given time there are hundreds of guinea pigs of all breeds and ages looking for new owners in shelters across every State, so adopt rather than breed!