Hi I am Ashlee from Pet Planet. I am in Riverton, Utah. I am here to help you to understand how to tell the difference between male and female on gerbils. Now these little gerbils right now are babies so they are too hard to determine if they are male female. Usually they are born with both two holes. The older they get the farther they grow apart if they are males so the farther they are from the other hole they're going to turn into a male. Also when they turn into adulthood you will start to see some testicles right underneath their tails which can help you determine whether it's a male or female. Usually at your local pet store when you go to purchase one and you want a certain male or female then they can actually help you. Usually they can determine the sex for you. If you have any questions you can always contact us at email@example.com. I will be happy to answer any of your questions.