You are unable to use Mac OS X Bluetooth adapter in a Virtual Machine; it is not listed or does not work when you click on it under Parallels Desktop USB menu.
This article applies to Parallels Desktop 7 and earlier. If you have Parallels Desktop 8 please check this article: https://kb.parallels.com/en/114686
Please perform the following steps to use the built-in Mac Bluetooth in Windows under Parallels Desktop:
NOTE: Before attempting these steps please make a Snapshot of your Virtual Machine by clicking on Virtual Machine menu ► Take Snapshot...
1) Run the Bootcamp Assistant (Applications->Utilities->Boot Camp Assistant) to download the latest Windows Support Software (Check only "Download the latest Windows Support Software from Apple" box, uncheck others)
Choose "Save a copy to an external drive" and in the next window choose one of your user's folders (for example, save it to your Downloads folder).
2) In your Windows virtual machine, download and install WinRAR application.
3) From your virtual machine, find the downloaded WindowsSupport folder on your Mac (you can access the file from Start->Computer->Home on 'psf'->Downloads)
4) Right-click on \WindowsSupport\Drivers\Apple\AppleBluetoothInstaller.exe, select Extract files (files are extracted by WinRAR). Remember where you put them (e.g., use the default location, "AppleBluetoothInstaller" folder).
4) Click Device and Printers in the Windows menu (Start->Device and Printers).
5) Bluetooth USB Host Controller should be mentioned below, but not functioning (if it is not mentioned, from the Parallels top menu, activate Devices > USB > Apple Bluetooth USB Host Controller).
Right-click on it, and select Properties. Then go to the Hardware tab, click Properties again, go to Details and from the Property top down list select Hardware Ids. Write down or copy the shortest line, for example:
7) Open Windows Explorer, go to the extracted files, locate AppleBT.inf file.
8) Double-click AppleBT.inf to edit it. Change
(Where the USB\VID… part is the line you copied as hardware id in step 5)
Save the changes.
9) Go back to Devices and Printers, right-click Bluetooth USB Host Controller, click Properties, go to the Hardware tab, click Properties, go to the Driver tab, click Update Drive, select Browse my computer for driver software, Browse to the location of where you extracted the files in Step 4), and click Next.