It has been possible to print double-sided since at least Lion/2008…
In Mac you need to print first one side, move the pages manually, print the other side. But you have to remember to add an extra page if the page count is odd, have caution if an app tries to be intelligent and sort the pages in a different way...
In Windows all those calculations are done by the system. It is easy! Just print and follow instructions. In Mac is painful.