Are my tot mice boys or girls?? How can i till?

My baby mice are 18 days old, and i can till that we need to separate them soon. So i call for to till which ones are girls and which ones are boys. So can you give my any good pictures?? PLEASE?
I really need lend a hand quick!
Thanks in advance!! =D
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Answers:    http://www.peteducation.com/article.cfm?...
http://www.thefunmouse.com/info/sexing.c...

They should minister to you but you some do so searching for sexing mice.
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Sexing young mice can be a little tricky. Put the mouse on your flat palm and near the other hand gently lift their bottom by the tail. The distance between the external genitals and their anus is what vary. With girls, they are fairly close and boys are further apart (to allow room for their testicles). Once the males are older, their testicles will be out most of the time, but they can retract them, making that unreliable.

For a good rule of thumb, use the mommy as a comparison for girl parts since you know she's feminine. The link below has a very honest side by side comparison of what 3 week old mice look like, so yours should be fairly similar. Hope this help! :)
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