How to differentiate the genders between guinea pigs. Actually, it’s quite simple to me. Here, I’ll share with you the Do’s and the Do not’s.

DO:

Handle your pet guinea pigs very gently and quietly. Cavies are easily scared and will squeal and struggle when frightened (which doesn’t help in trying to determine their gender).

Hold your guinea pigs firmly around the body (chest and shoulders). Scared guinea pigs can leap out of your hands if held loosely, resulting in injury (e.g. falling off a table top).
Perform guinea pig sexing or any guinea pig examination on the floor or on a very low table (e.g. short coffee table). This way, if the animal gets away, no injury will occur from the animal falling from a great height.

DO NOT:

Handle guinea pigs roughly when sexing guinea pigs.

Handle young guinea pigs if they are still suckling (not yet weaned) and their mother is clearly distressed by you handling them.

Hold guinea pigs loosely or leave them unattended on elevated surfaces. They will dash off a high table or bench top if frightened, leading to severe injury.

Male’s Genital Area.

Female’s Genital Area.

The Distance between the Genital to the Anus.

The Male.

The Female.

The Shape of the Genitals:

The Male.

The Female.

All information and pictures were gather from: http://www.pet-informed-veterinary-advice-online.com/sexing-guinea-pigs.html
All Copyright belongs to them. No infringement were intended, Only for the use of educational purposes.