Male gerbils can be neutered, as long as they are over the age of approximately five months. Any younger than this and responsible vets will refuse to perform the operation, as the animal is too young to go under that form of anaesthetic. Regardless of their age they will need to be checked to make sure they are of an adequate condition to be subjected to this form of operation.
Depending on where in the world you live, the operation will be priced differently. It will vary both according to the surgery itself and how common these operations are where you live. Residents of the United Kingdom can expect to pay anything between sixty to two hundred pounds for an operation of this kind, so if you have lots of surgeries nearby it really pays to shop around.
What does not change throughout the world is the fact that this operation will need to be performed by a small mammal veterinarian. Some surgeries don’t have small mammal vets working within them, so you’ll need to check that the the right expert is there before you take your pet to the surgery.
Gerbils can have the operation, but it's wise to consider other options first
Before you decide to give your pet this operation, it’s a good idea to consider whether or not it really needs it. If it’s being kept in a mixed-sex cage and there is no way that you can separate the genders without leaving a gerbil on its own, then yes, you will indeed need to neuter your males. However, if you have two males and two females in the same cage, another possibility is that you could get a separate enclosure for the males. Solutions like this may be worth considering before you go ahead with the neutering.
There are risks associated with all operations, particularly those that involve general anaesthetics. The older and less healthy your pet is then the greater the risk that complications occur, but they can happen to any pet of any age. It’s good to be aware that before the operation you’ll probably need to sign some forms allowing your vets to take emergency action should it be needed during the procedure.
One important thing that your vet should already know to do is to use internal stitches on this species. They are very good at grooming themselves, and any external stitches are likely to get pulled around by the gerbil itself or by their cage-mates.