Megan
Several others have suggested how to fix and prevent the problem. The first thing you should do is take a file backup. At least you can always get back to where you are now. Merge two specific people works well in my experience. If you look at the Edit menu you will see an option to Find Duplicate People. FTM looks for people it thinks are duplicate and gives you the option to merge them or not merge them.
Curt
Several others have suggested how to fix and prevent the problem. The first thing you should do is take a file backup. At least you can always get back to where you are now. Merge two specific people works well in my experience. If you look at the Edit menu you will see an option to Find Duplicate People. FTM looks for people it thinks are duplicate and gives you the option to merge them or not merge them.
Curt