Can I develop Mobile (Android and IOS) Games in Monogame?

This is no longer the case. Xamarin Studio is deprecated in favor of VS for Mac.

@Edgar_Acosta MG can install templates in VS for Mac. You should be able to find the add-in if you enable alpha channel. See also this topic: Add templates for Visual Studio Mac

It’s worth mentioning that the only thing MG installs for any IDE are the templates. The other stuff the installer does is completely IDE-independent.