There are two ways to export people in your file.
1) Main Menu > File > Export > Use a filter
2) Export people in a chart at Publish > Chart and right click in a blank space in the chart and choose "export all in this chart".
If you have no peripheral relatives, like parents and other relatives of spouses, step-children, etc, you can use Choice No. 1. Select Mom or Dad, and all ancestors, plus x generations of descendants.
But, since that is not how most of us research, you are bound to have lots of peripheral relatives.
In that case, you would detach yourself from one of your parents, then select one side and run an Extended Family Chart. The Extended Family Chart includes everybody related to the selected person in any way, shape, or form - either by blood or marriage - ie all peripheral relatives.
1) Detach yourself from either mom or dad. Select mom or dad.
2) Publish > Charts > Extended Family Chart
3) Be sure the option in right panel is unchecked for: "Include ALL individuals".
4) Type "99" in number of generations.
5) After report is available, right click, export all in this chart.
PS. The chart can both EXPORT and DELETE a group of individuals. You can ONLY Export at the Main Menu > Export option.
So, IF you are working with a backup and using the Extended Family Chart, you can EXPORT, then DELETE and have the two trees on your hard drive. Again, only do this with a backup or if the file is backed up.
If you use Option 1, the Main Menu > Export, you will have to Export twice - once for Mom's Side and once for Dad's side.
After you are done, compare the number of people in one file plus the other file to see if they add to the total people in the first file.