Printing options like printing even or odd pages is a feature provided by the users printer software, not by Firefox.

Are you using a different printer and print drivers?

If not, try resetting your printer preferences in Firefox.
https://support.mozilla.org/en-US/kb/fix-printing-problems-firefox#w_reset-all-firefox-printer-settings

If so, your current printer software may not offer that odd / even pages feature, or it may have a different name like two-side printing.

Yesterday I had all the options, but only in Internet Explorer. I used the even/odd page option with a large printing project. Today, after trying to correct the problem in Firefox, I no longer see the print options in IE. I should have left well enough alone. After receiving your reply I first reset the print_printer setting (from about:config) and that didn't work. Next I tried to Reset all Firefox printer settings. When I opened the prefs.js file in Wordpad I found no lines starting with print_ but did see numerous files starting with printer_ and print.printer. Should I delete those? I also did a system restore but that didn't bring back my printer options in Internet Explorer. Can you suggest other avenues I might explore? Thanks for your help.

Well I hope some of this helps, I learned using google chrome to use ctrl +P, so then I tried it in windows IE and firefox and it showed me options, better than what those browsers would. Also it is best to enter the control panel and open printer properties there, because those will be your default settings. Hope this helps!

Hornnumb2 posted the same problem and included screenshots of the printer pop-up, before and after the missing options. The suggested solution didn't work for me. The- edmeister suggested another fix above that involved resetting printer settings using pers.js. I tried that, but as you can see from my response above I didn't see print_ and wondered if I should delete all references beginning with printer_ and/or print.printer. I don't think my issue is with printer preferences, but with missing options such as the ability to choose to print even or odd pages only. Control P only brings up the same menu as File>print (with no option for even/odd). If my deleting these things messes up the prefs.js, where do I find the file so that I can copy the backup copy to it? Thanks for your repsonse.

Contact the printer manufacturer and see if there is an update or to see if they know what your problem might be. You might have to reinstall the printer software. Sorry I can't help further!